CN102548143B - Drive circuit, dimmer controller and method for electrically controlling light-emitting diode (LED) light source - Google Patents
Drive circuit, dimmer controller and method for electrically controlling light-emitting diode (LED) light source Download PDFInfo
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Abstract
The invention discloses a drive circuit, a dimmer controller and a method for electrically controlling a light-emitting diode (LED) light source. The drive circuit comprises a transformer, a switch controller and a dimmer controller. The transformer comprises a primary winding which is used for receiving the input electric energy from an alternating current/direct current converter and an auxiliary winding which provides the output electric energy for the LED light source. The switch controller is connected between an optical coupler and the primary winding, and is used for receiving a feedback signal which indicates the target value of the current which passes by the LED light source, and controlling the input electric energy of the primary winding according to the feedback signal. The dimmer controller is connected with the auxiliary winding, and is used for receiving a switch monitoring signal which indicates the motion of a power switch, and adjusting the output electric energy of the transformer through adjusting the feedback signal according to the switch monitoring signal. According to he invention, the brightness of the LED light source can be controlled without using other dimming devices, and accordingly, the cost is saved.
Description
Technical field
The present invention relates to a kind of light source driving circuit, relate in particular to a kind of drive circuit, light adjusting controller and method of LED light source being carried out to controlling electric energy.
Background technology
In recent years, the new type light source such as light-emitting diode (LED) is at material with manufacture and all obtained progress.LED has high efficiency, long-life, the feature such as bright-colored, can be applied to the fields such as automobile, computer, communication, military affairs and commodity.Such as, LED lamp can substitute traditional incandescent lamp as lighting source.
Figure 1 shows that a kind of schematic diagram of traditional LED drive circuit 100.LED drive circuit 100 utilizes LED chain 106 as light source.The LED that LED chain 106 comprises a plurality of series connection.Electric power converter 102 converts input voltage vin to the VD Vout of expectation, for giving LED chain 106 power supplies.The switch 104 being connected with electric power converter 102 is for controlling opening or closing of LED lamp.Electric power converter 102 receives from the feedback signal of current sense resistance R sen regulation output voltage Vout so that LED chain 106 produces the brightness of expectation.One of shortcoming of this traditional scheme is in use, and user cannot regulate the brightness of LED.
Figure 2 shows that the schematic diagram of another kind of traditional LED drive circuit 200.Electric power converter 102 converts input voltage vin to the VD Vout of expectation, for giving LED chain 106 power supplies.The switch 104 being connected with electric power converter 102 can be for controlling opening or closing of LED lamp.LED chain 106 is connected with linear current adjuster 208.Operational amplifier 210 comparison reference signal REF in linear current adjuster 208 and from the current monitoring signal of current sense resistance R sen, and produce control signal, in linear mode, regulate the resistance of transistor Q3, thereby the electric current of the LED chain 106 that makes to flow through can be regulated accordingly.This traditional LED drive circuit 200 need to utilize certain dedicated devices to regulate the brightness of LED chain 106, for example, utilize a custom-designed switch that has the switch of adjusting button or can receive remote signal, thereby cause cost to increase.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of drive circuit, light adjusting controller and method of LED source being carried out to controlling electric energy, does not need to use extra light modulation device just can realize the control to LED source brightness.
The invention provides a kind of drive circuit that LED source is carried out to controlling electric energy.Described drive circuit comprises transformer, on-off controller and light adjusting controller.Described transformer comprises for receiving from the former limit winding of the input electric energy of AC/DC converter with for described LED source provides the secondary winding of output electric energy.On-off controller is connected between optical coupler and described former limit winding, for receive the feedback signal of the desired value of the electric current of indicating the LED source of flowing through from described optical coupler, and according to described feedback signal, controls the input electric energy of described former limit winding.Light adjusting controller is connected with described secondary winding, for receiving the switch monitor signal and the current monitoring signal of indicating the electric current of the described LED source of flowing through of the action of indication mains switch, and produce compensating signal according to described switch monitor signal and described current monitoring signal, described compensating signal is adjusted described feedback signal via described optical coupler, to regulate the output electric energy of described transformer by adjusting described feedback signal.Wherein said mains switch is connected between AC power and described AC/DC converter.Light adjusting controller comprises: trigger monitoring means, for receiving described switch monitor signal and producing and drive signal according to the action of described mains switch; And the dimmer being connected with described triggering monitoring means, for producing dim signal to adjust described compensating signal according to described driving signal.Light adjusting controller works in pulse light modulation pattern, under pulse light modulation pattern, according to described dim signal, produce the first pulse width modulating signal, the duty ratio of described the first pulse width modulating signal is determined by described dim signal, and described the first pulse width modulating signal is adjusted described compensating signal and controlled the second switch of connecting with described LED source.
The present invention also provides a kind of light adjusting controller, and it is connected with the secondary winding of transformer, for controlling the electric energy to LED source from AC/DC converter.Described light adjusting controller comprises: switch monitoring port, current monitoring port and compensation port.Described switch monitoring port is for receiving the switch monitor signal of the action of indication mains switch, and wherein said mains switch is connected between AC power and described AC/DC converter.Described current monitoring port is for receiving the current monitoring signal of the electric current of indicating the described LED source of flowing through.Described compensation port is for producing compensating signal according to described switch monitor signal and described current monitoring signal, described compensating signal is via the flow through feedback signal of desired value of electric current of described LED source of optical coupler adjustment indication, thereby by adjusting described feedback signal, control the control switch with the former limit windings in series of described transformer, to adjust the electric energy of described LED source.Described light adjusting controller also comprises triggering monitoring means, for receiving described switch monitor signal from described switch monitoring port and producing and drive signal according to the action of described mains switch; And the dimmer being connected with described triggering monitoring means, for producing dim signal to adjust described compensating signal according to described driving signal.Light adjusting controller works in pulse light modulation pattern, under described pulse light modulation pattern, according to described dim signal, produce pulse width modulating signal, the duty ratio of described pulse width modulating signal is determined by described dim signal, and described pulse width modulating signal is adjusted described compensating signal and controlled the second switch of connecting with described LED source.
The present invention also provides a kind of method of LED source being carried out to controlling electric energy.Described method comprises: transformer provides the electric energy after adjusting to power to described LED source; Receive the feedback signal of the desired value of the electric current of indicating the described LED source of flowing through; Receive the switch monitor signal of the action of mains switch in the circuit of the former limit of indication; Receive the current monitoring signal of the electric current of indicating the described LED source of flowing through; According to described switch monitor signal, produce dim signal; According to described dim signal and described current monitoring signal, produce compensating signal; And adjust described feedback signal according to described compensating signal, to adjust the output electric energy of described transformer.According to the step of described dim signal and described current monitoring signal generation compensating signal, comprise: in the situation that adopting pulse light modulation pattern, according to described dim signal, produce pulse width modulating signal; And adjust described compensating signal according to described pulse width modulating signal.
By the method that adopts drive circuit of the present invention, light adjusting controller and light source is carried out to controlling electric energy, the brightness that can effectively control light source changes, especially when being coupled in mains switch between power supply and light source and connecting, can well avoid light-source brightness sudden change, and the brightness of light source is increased gradually, thereby for providing more comfortable user, user experiences.In addition, the present invention can pass through the action to common power switch, regulates the brightness of light source, and needn't use extra device as disconnected action, for example, without the custom-designed switch with light modulation button, thereby saves cost.
Accompanying drawing explanation
Below, by the description in conjunction with its accompanying drawing to some embodiments of the present invention, can further understand object of the present invention, specific structural features and advantage.
Figure 1 shows that a kind of circuit diagram of traditional LED drive circuit;
Figure 2 shows that the circuit diagram of another kind of traditional LED drive circuit;
Figure 3 shows that the schematic diagram of light source driving circuit according to an embodiment of the invention;
Figure 4 shows that the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 5 shows that the structural representation of the light adjusting controller in Fig. 4;
Figure 6 shows that the signal waveform schematic diagram under analog dimming mode;
Figure 7 shows that the signal waveform schematic diagram under pulse light modulation pattern;
Figure 8 shows that the operation chart of light source driving circuit according to an embodiment of the invention, this light source driving circuit includes the light adjusting controller shown in Fig. 5;
Figure 9 shows that the method flow diagram that according to an embodiment of the invention light source is carried out controlling electric energy;
Figure 10 shows that the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 11 shows that the structural representation of the light adjusting controller in Figure 10;
Figure 12-13 are depicted as the signal waveforms of light source driving circuit according to an embodiment of the invention, and this light source driving circuit includes the light adjusting controller shown in Figure 11;
Figure 14 shows that the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 15 shows that the structural representation of the light adjusting controller in Figure 14;
Figure 16 shows that the signal waveforms of light source driving circuit according to an embodiment of the invention, this light source driving circuit includes the light adjusting controller shown in Figure 15;
Figure 17 shows that the method flow diagram that according to an embodiment of the invention light source is carried out controlling electric energy;
Figure 18 shows that the schematic diagram of light source driving circuit according to an embodiment of the invention;
Figure 19 shows that the example of mains switch according to an embodiment of the invention;
Figure 20 shows that the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 21 is depicted as the structural representation of the light adjusting controller in Figure 20;
Figure 22 is depicted as the signal waveforms of light source driving circuit under analog dimming mode according to an embodiment of the invention, and this light source driving circuit includes the light adjusting controller shown in Figure 21;
Figure 23 is depicted as the circuit diagram of light source driving circuit according to an embodiment of the invention;
Figure 24 is depicted as the structural representation of the light adjusting controller in Figure 23;
Figure 25 is depicted as the signal waveforms of light source driving circuit under pulse light modulation pattern according to an embodiment of the invention, and this light source driving circuit includes the light adjusting controller shown in Figure 24;
Figure 26 is depicted as the method flow diagram that according to an embodiment of the invention light source is carried out controlling electric energy.
Embodiment
To embodiments of the invention be provided to detailed reference below.Although the present invention is set forth and illustrated by these execution modes, it should be noted that the present invention is not merely confined to these execution modes.On the contrary, all substitutes, variant and the equivalent in the defined invention spirit of claims and invention scope contained in the present invention.
In addition, for better explanation the present invention, in embodiment below, provided numerous details.It will be understood by those skilled in the art that and there is no these details, the present invention can implement equally.In other example, the method for knowing for everybody, formality, element and circuit are not described in detail, so that highlight purport of the present invention.
Figure 3 shows that the schematic diagram of light source driving circuit 300 according to an embodiment of the invention.In one embodiment, light source driving circuit 300 comprises for the AC-input voltage Vin from power supply being converted to the AC/DC converter 306 of VD Vout, be connected in the mains switch 304 for selectivity connection power supply and light source driving circuit 300 between power supply and AC/DC converter 306, the LED chain 312 that is used to being connected with AC/DC converter 306 provides the electric power converter 310 that regulates rear electric energy, be connected with electric power converter 310 for receiving the switch monitor signal of indication mains switch 304 actions, according to this switch monitor signal, control the light adjusting controller 308 of electric power converter 310 outputs, and for monitoring stream the current monitor 314 through the electric current of LED chain 312.In one embodiment, mains switch 304 can be the mains switch being placed on metope.By the handle in diverter switch, user can control the conducting state of mains switch 304.Figure 19 shows the example of mains switch 304 according to an embodiment of the invention.
In operation, AC/DC converter 306 is converted to VD Vout by input ac voltage Vin.Electric power converter 310 receives direct voltage Vout and provides the voltage after adjusting for LED chain 312.Current monitor 314 generation current monitor signals, the flow through size of electric current of LED chain 312 of this current monitoring signal designation.The action of light adjusting controller 308 monitoring mains switches 304, receives the current monitoring signal from current monitor 314, and according to the action control electric power converter 310 of mains switch 304 to regulate the electric energy of LED chain 312.In one embodiment, light adjusting controller 308 works in analog dimming mode, by regulating the reference signal of a decision LED lowest high-current value to regulate the electric energy of LED chain 312.In another embodiment, light adjusting controller 308 works in pulse light modulation (burst dimming) pattern, by regulating the duty of a pulse width modulating signal (pwm signal) recently to regulate the electric energy of LED chain 312.By regulating the electric energy of LED chain 312, the brightness of LED chain 312 can access accordingly and regulate.
Figure 4 shows that the circuit diagram of light source driving circuit 400 according to an embodiment of the invention.Fig. 4 is described in connection with Fig. 3.Parts identical with Fig. 3 label in Fig. 4 have similar function, are not repeated in this description for simplicity's sake at this.
Light source driving circuit 400 comprises the electric power converter 310 being connected between power supply and LED chain 312, for receiving from the electric energy of power supply and for LED chain 312, provides the electric energy after adjusting.In the embodiment of Fig. 4, electric power converter 310 is the step-down controllers that comprise inductance L 1, diode D4 and control switch Q16.In embodiment in Fig. 4, control switch Q16 is positioned at the outside of light adjusting controller 308.In other embodiment, control switch Q16 also can be integrated in the inside of light adjusting controller 308.
Light adjusting controller 308 receiving key monitor signals also control according to this switch monitor signal the switch Q16 connecting with LED chain 312, to regulate the electric energy after the adjusting that electric power converter 310 exports.The action of this switch monitor signal indication mains switch 304.Light source driving circuit 400 further comprises AC/DC converter 306, for converting AC-input voltage Vin to VD Vout.Light source driving circuit 400 also comprises current monitor 314, the electric current for monitoring stream through LED chain 312.In the embodiment shown in fig. 4, AC/DC converter 306 is the bridge rectifiers that comprise diode D1, D2, D7, D8, D10 and capacitor C 9.Current monitor 314 comprises current sense resistance R 5.
In one embodiment, the port of light adjusting controller 308 comprises: HV_GATE, SEL, CLK, RT, VDD, CTRL, MON and GND.Port HV_GATE is connected with switch Q27 by resistance R 3, for controlling the conducting state of the switch Q27 being connected with LED chain 312, for example, the state of the on/off of switch Q27.Capacitor C 11 is connected between port HV_GATE and ground, for adjusting the grid voltage of switch Q27.
User can select port SEL to be connected to ground by resistance R 4, as shown in Figure 4, or port SEL is directly connected to ground, can correspondingly select analog dimming mode or pulse light modulation pattern.
Port CLK is connected to AC/DC converter 306 by resistance R 3, is connected to ground by resistance R 6 simultaneously.Port CLK receives a switch monitor signal, the action of this switch monitor signal indication mains switch 304.In one embodiment, switch monitor signal produces on a node between resistance R 3 and resistance R 6.Capacitor C 12 is in parallel with resistance R 6, for the unnecessary noise of filtering.Port RT is connected to the ground by resistance R 7, for determining the frequency of the pulse signal being produced by light adjusting controller 308.
Port VDD is connected with switch Q27 by diode D9, is used to light adjusting controller 308 power supplies.In one embodiment, an energy-storage units, as capacitor C 10 be connected in port VDD and between, when mains switch 304 disconnects, be light adjusting controller 308 power supplies.In another embodiment, energy-storage units is integrated in light adjusting controller 308 inside.Port GND is connected to the ground.
Port CTRL is connected with switch Q16.Switch Q16 connects with LED chain 312 and switch Q27, and is connected to ground by current monitoring resistance R 5.Light adjusting controller 308 is by the conducting state of the control signal control switch Q16 that exports on port CTRL, to adjust the electric energy after the adjusting of electric power converter 310 outputs.Port MON is connected with current monitoring resistance R 5, for receiving the current monitoring signal of the electric current of indicating the LED chain 312 of flowing through.When switch Q27 connects, light adjusting controller 308 regulates the electric current of the LED chain 312 of flowing through by control switch Q16.
In operation, when mains switch 304 is connected, AC/DC converter 306 is converted to VD Vout by the alternating voltage Vin of input.The voltage on port HV_GATE with predeterminated voltage value puts on switch Q27 above by resistance R 3, thus turn on-switch Q27.
If light adjusting controller 308 turn on-switch Q16, direct voltage Vout can be to 312 power supplies of LED chain and to inductance L 1 charging.Electric current is flowed through inductance L 1, LED chain 312, switch Q27, switch Q16 and resistance R 5 to ground.If light adjusting controller 308 cut-off switch Q16, flow through inductance L 1, LED chain 312 and diode D4 of electric current.Inductance L 1 discharges to power to LED chain 312.Therefore, light adjusting controller 308 is by control switch Q16, can adjust the electric energy after the adjusting of electric power converter 310 outputs.
When mains switch 304 disconnects, light adjusting controller 308 power supplies are thought in capacitor C 10 electric discharges.The voltage drop to 0 at resistance R 6 two ends, thus light adjusting controller 308 can monitor the switch monitor signal of indication mains switch 304 opening operations on port CLK.Similarly, when mains switch 304, connect, the voltage at resistance R 6 two ends rises to a predeterminated voltage value, thereby light adjusting controller 308 can monitor the switch monitor signal of indication mains switch 304 making operations on port CLK.If monitor opening operation, light adjusting controller 308 can pull down to 0 with cut-off switch Q27 by the voltage on port HV_GATE, thereby after inductance L 1 is thoroughly discharged, LED chain 312 is de-energized.And if monitor after the opening operation of mains switch 304 reference signal of light adjusting controller 308 adjustings, the expectation brightness of this reference signal indication LED chain 312.When mains switch connection 304 next time, the brightness of LED chain 312 can be adjusted according to the expectation brightness after regulating.In other words, the output brightness of LED chain 312 can be adjusted according to the opening operation of mains switch 304 by light adjusting controller 308.
Figure 5 shows that the structural representation of the light adjusting controller 308 in Fig. 4.Fig. 5 is described in connection with Fig. 4.Parts identical with Fig. 4 label in Fig. 5 have similar function, are not repeated in this description for simplicity's sake at this.
In one embodiment, if the voltage on port VDD, higher than the first predeterminated voltage, starts and low pressure lock-in circuit 508 will start all parts in light adjusting controller 308.When mains switch 304 disconnects, if the voltage on port VDD, lower than the second predeterminated voltage, starts and low pressure lock-in circuit 508 will cut out in light adjusting controller 308 miscellaneous part except triggering monitoring means 506 and dimmer 502 with saving electric energy.If the voltage on port VDD, lower than the 3rd predeterminated voltage, starts and low pressure lock-in circuit 508 will cut out parts all in light adjusting controller 308.In one embodiment, the first predeterminated voltage is higher than the second predeterminated voltage, and the second predeterminated voltage is higher than the 3rd predeterminated voltage.Because light adjusting controller 308 can be powered through port VDD by capacitor C 10, so even if after mains switch 304 disconnections, trigger monitoring means 506 and dimmer 502 and can also work a period of time.
In light adjusting controller 308, port SEL is connected with current source 532.User can select light-modulating mode by configured port SEL, for example, port SEL is directly connected to the ground, or port SEL is connected to the ground by a resistance.In one embodiment, light-modulating mode decides by the voltage on measurement port SEL.If port SEL is directly connected to the ground, the voltage on port SEL is similar to 0.In this case, a control circuit (not shown in Fig. 5) turn on-switch 540, cut-off switch 541 and switch 542, thus light adjusting controller 308 can work in analog dimming mode, and by adjusting reference signal REF, adjust the electric energy of LED chain 312.In another embodiment, if port SEL by resistance R 4 be connected to (as shown in Figure 4), the voltage on port SEL is greater than 0 so.This control circuit cut-off switch 540, turn on-switch 541 and switch 542, thus light adjusting controller 308 works in pulse light modulation pattern, and by adjusting the duty of pulse width modulating signal PWM1, recently adjust the electric energy of LED chain 312.In other words, by control switch 540, switch 541, the conducting state of switch 542, can select different light-modulating modes.And switch 540, switch 541, the conducting state of switch 542 is determined by the voltage on port SEL.
Pulse signal producer 504 is connected to ground by port RT and resistance R 7, produces the pulse signal 536 for turn on-switch Q16.Pulse signal producer 504 can have different structures, is not limited to the structure shown in Fig. 5.
In pulse signal producer 504, the in-phase end of operational amplifier 510 receives predeterminated voltage V1, so the end of oppisite phase voltage of operational amplifier 510 is also V1.Electric current I
rTby port RT and resistance R 7, flow to ground.The flow through electric current I of mos field effect transistor (MOSFET) 514 and mos field effect transistor 515
1with electric current I
rTthere is same size.Mos field effect transistor 514 and mos field effect transistor 512 form current mirror, the electric current I of the mos field effect transistor 512 of therefore flowing through
2also with electric current I
rTthere is identical size.The output of the output of comparator 516 and comparator 518 is connected with R input with the S input of set-reset flip-floop 520 respectively.The end of oppisite phase of comparator 516 receives predeterminated voltage V2.The in-phase end of comparator 518 receives predeterminated voltage V3.In one embodiment, V2 is greater than V3, and V3 is greater than 0.Capacitor C 4 is connected between mos field effect transistor 512 and ground, and one end is connected with the node between comparator 516 in-phase ends and comparator 518 end of oppisite phase.The Q output of set-reset flip-floop 520 is connected with switch Q15, is also connected with the S input of set-reset flip-floop 522 simultaneously.Switch Q15 is in parallel with capacitor C 4.The conducting state of switch Q15 is determined by the Q output of set-reset flip-floop 520.
The initial voltage at capacitor C 4 two ends is approximately 0, is less than V3.Therefore, the R input of set-reset flip-floop 520 receives the digital signal 1 of comparator 518 outputs.The Q output of set-reset flip-floop 520 is set to digital signaling zero, thus cut-off switch Q15.When switch Q15 disconnects, capacitor C 4 is in electric current I
2effect under charge, so the voltage at capacitor C 4 two ends raises.When C4 both end voltage is greater than V2, the S input of set-reset flip-floop 520 receives the digital signal 1 of comparator 516 outputs.The Q output of set-reset flip-floop 520 is set to digital signal 1, thus turn on-switch Q15.When switch Q15 connects, capacitor C 4 is discharged by switch Q15, thus the lower voltage at two ends.When the voltage drop at capacitor C 4 two ends is to V3, comparator 518 output digit signals 1, the Q output of set-reset flip-floop 520 is set to digital signaling zero, thus cut-off switch Q15.After this capacitor C 4 is in electric current I
2effect under charge again.As previously mentioned, pulse signal producer 504 produces pulse signal 536 at the Q of set-reset flip-floop 520 output, and this pulse signal 536 includes a series of pulse.Pulse signal 536 is transferred into the S input of set-reset flip-floop 522.
Trigger monitoring means 506 by the action of port CLK monitoring mains switch 304.If the action of mains switch 304 is monitored at port CLK, triggers monitoring means 506 and produce a driving signal with actuation counter 526.In one embodiment, when mains switch 304 is switched on, voltage on port CLK rises, and this voltage equals resistance R 6(as shown in Figure 4) voltage at two ends.When mains switch 304 is disconnected, the voltage drop to 0 on port CLK.Therefore, the switch monitor signal of indication mains switch 304 actions can be monitored at port CLK.In one embodiment, when one disconnects action when port CLK is monitored to, triggering monitoring means 506 generation driving signals.
Trigger monitoring means 506 also by the conducting state of port HV_GATE control switch Q27.When mains switch 304 is switched on, the puncture voltage at Zener diode ZD1 two ends is applied to switch Q27 by resistance R 3, thus turn on-switch Q27.Thereby trigger monitoring means 506 and the voltage of port HV_GATE can be pulled down to 0 cut-off switch Q27.In one embodiment, on port CLK, monitor the disconnection action of mains switch 304, trigger monitoring means 506 with regard to cut-off switch Q27.On port CLK, monitor the ON Action of mains switch 304, trigger monitoring means 506 with regard to turn on-switch Q27.
In one embodiment, dimmer 502 comprises the counter 526 being connected with triggering monitoring means 506, for the action of mains switch 304 is counted.Dimmer 502 also comprises the digital to analog converter 528 being connected with counter 526, and the pulse width modulating signal generator 530 being connected with digital to analog converter 528.Counter 526 is driven by the driving signal that triggers monitoring means 506 generations.Specifically, when mains switch 304 disconnects, trigger monitoring means 506 and on port CLK, monitor a trailing edge, thereby produce one, drive signal.The count value of counter 526 increases progressively under the effect of this driving signal.For example add 1.Digital to analog converter 528 reads count value from counter 526, and produces dim signal according to count value, and for example this dim signal can be control signal 538 or reference signal REF.Dim signal can be used for adjusting the target energy value of electric power converter 310, thereby adjusts the brightness of LED chain 312.
Under pulse light modulation pattern, switch 540 disconnects, and switch 541 and switch 542 are connected.The end of oppisite phase of comparator 534 receives reference signal REF1.Reference signal REF1 is the direct current signal with predeterminated voltage value.The voltage of reference signal REF1 has determined the lowest high-current value of LED chain 312, thereby has also determined the high-high brightness of LED chain 312.Under this pulse light modulation pattern, dim signal puts on the control signal 538 on pulse width modulating signal generator 530, can adjust the duty ratio of pulse width modulating signal PWM1.By adjusting the duty ratio of PWM1, make the brightness of LED chain 312 be equal to or less than the high-high brightness that reference signal REF1 determines.For example, if the duty ratio of PWM1 is 100%, LED chain 312 has high-high brightness.If the duty ratio of PWM1 is less than 100%, the brightness of LED chain 312 is lower than high-high brightness.
Under analog dimming mode, switch 540 is connected, and switch 541 and switch 542 disconnect.Under this analog dimming mode, dim signal is reference signal REF.This reference signal REF is an analog signal, has adjustable voltage.Digital to analog converter 528 is adjusted the voltage of reference signal REF according to the count value of counter 526.The voltage of reference signal REF has determined the lowest high-current value of LED chain 312, thereby has also determined the high-high brightness of LED chain 312.Therefore,, by adjusting reference signal REF, the brightness of LED chain 312 can correspondingly be adjusted.
In one embodiment, the count value increase of counter makes digital to analog converter 528 turn down the voltage of reference signal REF.For example, if count value is 0, the voltage that digital to analog converter 528 is adjusted reference signal REF is V4.If trigger monitoring means 506, monitor the disconnection action of mains switch 304 at port CLK, thereby make count value be increased to 1, the voltage that digital to analog converter 528 is adjusted reference signal REF is V5, and V5 is less than V4.In another embodiment, the count value increase of counter makes digital to analog converter 528 heighten the voltage of reference signal REF.
In one embodiment, when the count value of counter 526 reaches maximum, count value is set to 0 again.If counter 526 is two digit counters, count value will be increased to 1,2,3 successively since 0, then after the 4th opening operation, get back to 0.Accordingly, the brightness of LED chain 312 is adjusted to the second level successively from the first order, the third level, and the fourth stage, then gets back to again the first order.
The end of oppisite phase of comparator 534 can optionally receive reference signal REF or reference signal REF1.Under analog dimming mode, the end of oppisite phase of comparator 534 receives reference signal REF by switch 540.Under pulse light modulation pattern, the end of oppisite phase of comparator 534 receives reference signal REF1 by switch 541.The in-phase end of comparator 534 is connected with current monitoring resistance R 5 by port MON, to receive the current monitoring signal SEN from current monitoring resistance R 5.The voltage of current monitoring signal SEN represents the size of current of the LED chain 312 of flowing through when switch Q27 and switch Q16 connection.
The output of comparator 534 is connected with the R input of set-reset flip-floop 522.The Q output of set-reset flip-floop 522 be connected with door 524.The pulse width modulating signal PWM1 that pulse width modulating signal generator 530 produces is applied to and door 524.With door 524 output control signals, by port CTRL control switch Q16.
If selected analog dimming mode, switch 540 is connected, and switch 541 and switch 542 disconnect.Switch Q16 is controlled by set-reset flip-floop 522.When mains switch 304, connect, the puncture voltage at Zener diode ZD1 two ends is connected switch Q27.Under the effect of the pulse signal 536 producing at pulse signal producer 504, set-reset flip-floop 522 produces digital signal 1 at Q output, and switch Q16 is connected.Electric current is flowed through inductance L 1, LED chain 312, switch Q27, switch Q16, current monitoring resistance R 5 to ground.Because inductance L 1 stops the saltus step of electric current, this electric current can increase gradually.The voltage at current monitoring resistance R 5 two ends (being the voltage of current monitoring signal SEN) can increase thereupon.When the voltage of SEN is greater than the voltage of reference signal REF, comparator 534 output digit signals 1 are to the R input of set-reset flip-floop 522, thereby set-reset flip-floop 522 output digit signals 0 disconnect switch Q16.After switch Q16 disconnects, inductance L 1 electric discharge is to power to LED chain 312.The electric current of the inductance L of flowing through 1, LED chain 312 and diode D4 reduces gradually.When set-reset flip-floop 522 is when S input receives a pulse, switch Q16 connects, and the electric current of LED chain 312 flows to ground by current monitoring resistance R 5.When the voltage of current monitoring signal SEN is greater than the voltage of reference signal REF, switch Q16 is disconnected by set-reset flip-floop 522 again.As mentioned above, reference signal REF determined the to flow through peak value of LED chain 312 electric currents, also determined the brightness of LED chain 312.Therefore,, by adjusting reference signal REF, the brightness of LED chain 312 is correspondingly adjusted.
Under analog dimming mode, when triggering monitoring means 506 when port CLK monitors the disconnection action of mains switch 304, the count value of counter 526 adds 1.The disconnection action of mains switch 304 makes to trigger monitoring means 506 cut-off switch Q27.The change of count value makes digital to analog converter 528 from the first magnitude of voltage, adjust to second voltage value with reference to the voltage of signal REF.Therefore,, when mains switch 304 is connected again, the brightness of LED chain 312 is adjusted because of the adjustment of reference signal REF.
If strobe pulse light-modulating mode, switch 540 disconnects, and switch 541 and switch 524 are connected.The end of oppisite phase of comparator 534 receives the reference signal REF1 with predeterminated voltage value.Switch Q16 by set-reset flip-floop 522 and pulse width modulating signal PWM1 by with door 524 co-controllings.Reference signal REF1 has determined the peak current of LED chain 312, has also determined the high-high brightness of LED chain 312.The duty ratio of pulse width modulating signal PWM1 has determined the on/off time of switch Q16.When pulse width modulating signal PWM1 is digital signal 1, the conducting state of switch Q16 is determined by the output of the Q output of set-reset flip-floop 522.When pulse width modulating signal PWM1 is digital signaling zero, switch Q16 disconnects.By adjusting the duty ratio of pulse width modulating signal PWM1, can adjust accordingly the electric energy of LED chain 312.So reference signal REF1 and pulse width modulating signal PWM1 determine the brightness of LED chain 312 jointly.
Under pulse light modulation pattern, the opening operation of mains switch 304 monitors at the port CLK monitoring means 506 that is triggered.Triggering monitoring means 506 disconnects Q27 and produces driving signal.At this, drive under the effect of signal, the count value of counter 526 increases, for example, add 1.Digital to analog converter 528 produces control signal 538, makes the duty ratio of pulse width modulating signal PWM1 become the second level from the first order.Therefore,, when mains switch 304 is connected again, the brightness of LED chain 312 will be take target brightness value and be adjusted as target.And this target brightness value is determined jointly by reference signal REF1 and pulse width modulating signal PWM1.
Figure 6 shows that the signal waveform schematic diagram under analog dimming mode.Comprising the electric current 602 of the LED chain 312 of flowing through, pulse signal 536, the output V522 of set-reset flip-floop 522, with the output V524 of door 524, and the ON/OFF state of switch Q16.Fig. 6 is described in connection with Fig. 4 and Fig. 5.
Pulse signal producer 504 produces pulse signal 536.Under the effect of pulse signal 536 each pulse, set-reset flip-floop 522 produces digital signal 1 at Q output.And set-reset flip-floop 522 can make switch Q16 connect in Q output generation digital signal 1.When switch Q16 connects, inductance L 1 charging, electric current 602 increases.When electric current 602 reaches peak I max, be also the voltage of current monitoring signal SEN and the voltage of reference signal REF while equating, comparator 534 output digit signals 1, to the R input of set-reset flip-floop 522, make set-reset flip-floop 522 at Q output output digit signals 0.Set-reset flip-floop 522 can make switch Q16 disconnect at Q output output digit signals 0, and inductance L 1 electric discharge is 312 power supplies of LED chain, and electric current 602 reduces.Under analog dimming mode, by adjusting reference signal REF, the average current value of the LED chain 312 of flowing through is correspondingly adjusted, thereby the brightness of LED chain 312 is also adjusted.
Figure 7 shows that the signal waveform schematic diagram under pulse light modulation pattern.Comprising the electric current 602 of the LED chain 312 of flowing through, pulse signal 536, the output V522 of set-reset flip-floop 522, with the output V524 of door 524, the ON/OFF state of switch Q16 and pulse width modulating signal PWM1.Fig. 7 is described in connection with Fig. 4 and Fig. 5.
When PWM1 is digital signal 1, the electric current 602 of the LED chain 312 of flowing through, pulse signal 536, V522, the correlation between V524 and the ON/OFF state of switch Q16 is similar to Fig. 6.When PWM1 is digital signaling zero, becomes digital signaling zero with the output of door 524, thereby switch Q16 is disconnected and electric current 602 reduces.If PWM1 keeps the state long enough of digital signaling zero, electric current 602 can be reduced to 0.Under pulse light modulation pattern, by adjusting the duty ratio of PWM1, the average current value of the LED chain 312 of flowing through is adjusted accordingly, thereby the brightness of LED chain 312 is also adjusted.
Figure 8 shows that the implementation schematic diagram of light source driving circuit according to an embodiment of the invention.Fig. 8 is described in connection with Fig. 5.
In the embodiment shown in Fig. 8, the disconnection that monitors mains switch 304 whenever triggering monitoring means 506 is moved, and the count value of counter 526 will add 1.Counter 526 is two digit counters, and maximum count value is 3.
Under analog dimming mode, digital to analog converter 528 reads count value from counter 526.The increase of count value makes digital to analog converter 528 turn down the voltage of reference signal REF.The voltage of reference signal REF has determined the lowest high-current value Imax of LED chain 312, has also determined the mean value of LED chain 312 electric currents.Under pulse light modulation pattern, digital to analog converter 528 reads count value from counter 526.The increase of count value makes digital to analog converter 528 turn down the duty ratio of pulse width modulating signal PWM1, for example, turn down 25% at every turn.Counter 526 is reaching maximum count value, for example, be reset after 3.
Figure 9 shows that the method flow diagram that according to an embodiment of the invention light source is carried out controlling electric energy.Fig. 9 is described in connection with Fig. 4 and Fig. 5.
In step 902, electric power converter, for example, electric energy after the adjusting that electric power converter 310 provides is to light source, and for example LED chain 312 is powered.
In step 904, receiving key monitor signal, for example, receive this switch monitor signal by light adjusting controller 308.The mains switch of this switch monitor signal indication between power supply and electric power converter, for example action of mains switch 304.
In step 906, according to switch monitor signal, produce dim signal.
In step 908, according to described dim signal, control the switch of connecting with light source, switch Q16 for example, to adjust the electric energy after the adjusting that electric power converter provides.
In an embodiment who adopts analog dimming mode, by dim signal relatively with represent that the current monitoring signal of source current size adjusts electric power converter.At another, adopt in the embodiment of pulse light modulation pattern, by control the duty of a pulse width modulating signal with described dim signal, recently adjust electric power converter.
As previously mentioned, the present invention discloses a kind of light source driving circuit, this light source driving circuit is according to indication mains switch, and for example the switch monitor signal of fixing mains switch action is on the wall adjusted the electric energy of light source.The electric energy of this light source is provided by electric power converter, and is adjusted by controlling the switch of connecting with light source by light adjusting controller.
User can pass through the action to a common low-cost mains switch, for example, disconnect action, and regulate the brightness of light source, and needn't use extra device, the custom-designed switch with light modulation button for example, thus save cost.
Figure 10 shows that the circuit diagram of light source driving circuit 1000 according to an embodiment of the invention.Parts identical with Fig. 4 label in Figure 10 have similar function.In structure as shown in figure 10, if the mains switch 304 being coupled between power supply and light source driving circuit 1000 is connected, light source driving circuit 1000 increases light source gradually, for example the brightness of LED chain 312.
In one embodiment, light source driving circuit 1000 comprises electric power converter 310 and light adjusting controller 1008.Electric power converter 310 and power supply and 312 couplings of LED chain.Electric power converter 310 receives electric energy that power supplys provide and provides the electric energy after adjusting for LED chain 312.In the embodiment of Figure 10, electric power converter 310 is the step-down controllers that comprise inductance L 1, diode D4 and control switch Q16.In Figure 10, control switch Q16 can be positioned at light adjusting controller 1008 outsides.In other embodiments, control switch Q16 also can be integrated in light adjusting controller 1008 inside.Electric energy after the adjusting that the control switch Q16 that light adjusting controller 1008 is connected with LED chain 312 by control provides with adjustment electric power converter 310.In one embodiment, light adjusting controller 1008 is according to the flow through electric current of LED chain 312 of a ramp signal adjustment, makes the average current of LED chain 312 when being coupled in mains switch 304 between power supply and light source driving circuit 1000 and connecting increase to gradually preset value.
Light source driving circuit 1000 also comprises for AC-input voltage Vin being converted to the AC/DC converter 306 of VD Vout, and monitoring stream is through the current monitor 314 of LED chain 312 electric currents.In the embodiment of Figure 10, AC/DC converter 306 is the bridge rectifiers that consist of diode D1, D2, D7, D8, D10 and capacitor C 9.Current monitor 314 comprises current monitoring resistance R 5.
In the embodiment of Figure 10, light adjusting controller 1008 has port HV_GATE, SST, LCT, RT, VDD, CTRL, MON and GND.Port HV_GATE is coupled with switch Q27 by resistance R 3, for the conducting state of control switch Q27.Capacitor C 11 is coupled between port HV_GATE and ground, and for switch, Q27 provides grid voltage.Port SST is by capacitor C 20 and ground coupling, for receiving ramp signal.Port LCT is by capacitor C 12 and ground coupling.Port RT is by resistance R 7 and ground coupling, for determining the frequency of the pulse signal that light adjusting controller 1008 produces.Port VDD is coupled by diode D9 and switch Q27, is light adjusting controller 1008 power supplies.In one embodiment, be coupled in the energy-storage units between port VDD and ground, for example capacitor C 10, are light adjusting controller 1008 power supplies when mains switch 304 disconnects.In another embodiment, energy-storage units is integrated in light adjusting controller 1008 inside.Port GND is connected to the ground.
Port CTRL and control switch Q16 coupling.Control switch Q16 connects with LED chain 312, switch Q27 and current monitoring resistance R 5.Electric energy after the adjusting that light adjusting controller 1008 provides with adjustment electric power converter 310 by the conducting state of utilizing the control signal of port CTRL output to control this control switch Q16.Port MON and 5 couplings of current monitoring resistance R, receive the current monitoring signal of indicating LED chain 312 electric currents of flowing through.When switch Q27 connects, light adjusting controller 1008 is adjusted the electric current of the LED chain 312 of flowing through by controlling control switch Q16.
When mains switch 304, connect, AC/DC converter 306 is converted to VD Vout by AC-input voltage Vin.Thereby the predeterminated voltage on port HV_GATE puts on switch Q27 turn on-switch Q27 by resistance R 3.If light adjusting controller 1008 is connected control switch Q16, direct voltage Vout is 312 power supplies of LED chain and inductance L 1 is charged.Electric current is flowed through inductance L 1, LED chain 312, switch Q27, control switch Q16, current monitoring resistance R 5 to ground.If light adjusting controller 1008 disconnects control switch Q16, electric current flow through inductance L 1, LED chain 312 and diode D4.Inductance L 1 electric discharge is 312 power supplies of LED chain.Therefore, light adjusting controller 1008, by controlling control switch Q16, is adjusted the electric energy of electric power converter 310.
Figure 11 shows that the structural representation of the light adjusting controller 1008 in Figure 10.The parts identical with label in Fig. 5 have similar function.
In the embodiment of Figure 11, light adjusting controller 1008 comprises pulse signal producer 504, pulse width modulating signal generator 1108 and startup and low pressure lock-in circuit 508.Startup and low pressure lock-in circuit 508 optionally start one or more parts of light adjusting controller 1008 inside according to the different electric energy situation of light adjusting controller 1008.Pulse signal producer 504 produces pulse signal to connect control switch Q16.Pulse width modulating signal generator 1108 produces pulse width modulating signal PWM2.In one embodiment, pulse width modulating signal generator 1108 comprises sawtooth signal generator 1102 for generation of sawtooth signal SAW, for generation of the power supply 1104 of ramp signal RAMP1, and the comparator 1106 that sawtooth signal SAW and ramp signal RAMP1 is compared to produce pulse width modulating signal PWM2.
Pulse signal producer 504 produces the pulse signal 536 that comprises a series of pulses at the Q of set-reset flip-floop 520 output.Pulse signal 536 is transferred into the S input of set-reset flip-floop 522.The end of oppisite phase of comparator 534 receives reference signal REF2.Reference signal REF2 is the direct current signal with predeterminated voltage value.In the embodiment of Figure 11, the voltage of REF2 has determined the lowest high-current value of LED chain 312, thereby has also determined the high-high brightness of LED chain 312.The output of comparator 534 is connected with the R input of set-reset flip-floop 522.The Q output of set-reset flip-floop 522 be connected with door 524.The pulse width modulating signal PWM2 that pulse width modulating signal generator 1108 produces is sent to and door 524.With door 524 output control signals, by port CTRL, control Q16.In one embodiment, when pulse width modulating signal PWM2 is digital signal 1, the conducting state of switch Q16 is determined by the output of the Q output of set-reset flip-floop 522.When pulse width modulating signal PWM2 is digital signaling zero, switch Q16 disconnects.By adjusting the duty ratio of pulse width modulating signal PWM2, can adjust accordingly the electric energy of LED chain 312.So reference signal REF2 and pulse width modulating signal PWM2 determine the brightness of LED chain 312 jointly.
Figure 12,13 is depicted as the signal waveforms of light source driving circuit according to an embodiment of the invention, and this light source driving circuit includes the light adjusting controller 1008 shown in Figure 11.Figure 12 shows the waveform of sawtooth signal SAW, ramp signal RAMP1 and pulse width modulating signal PWM2.Figure 13 shows electric current 602, the pulse signal 536 of the LED chain 312 of flowing through, the output V522 of set-reset flip-floop 522, with conducting state and the pulse width modulating signal PWM2 of output V524, the control switch Q16 of door 524.Figure 12 and Figure 13 describe in connection with Figure 10 and Figure 11.
When mains switch 304, connect, light adjusting controller 1008 receives electric energy by port VDD.If the voltage of port VDD is greater than predeterminated voltage value, start and low pressure lock-in circuit 508 startup power supplys 1104, by port SST, be capacitor C 20 chargings.The voltage at capacitor C 20 two ends (being also ramp signal RAMP1) increases gradually, as shown in figure 12.Sawtooth signal generator 1102 produces sawtooth signal SAW.Comparator 1106 comparison ramp signal RAMP1 and sawtooth signal SAW are to produce pulse width modulating signal PWM2.Therefore,, if mains switch 304 is connected, the duty ratio of pulse width modulating signal PWM2 is along with the voltage of ramp signal RAMP1 increases and increases, as shown in figure 12.
Pulse signal producer 504 produces pulse signal 536.In pulse signal 536, under the effect of each pulse, set-reset flip-floop 522 produces digital signal 1 at Q output.If pulse width modulating signal PWM2 is digital signal 1, set-reset flip-floop 522 produces digital signal 1 at Q output control switch Q16 is connected, and the electric current of the inductance L of flowing through 1 increases, and LED electric current 602 increases.When LED electric current 602 increases to maximum Imax, illustrate that the voltage of current monitoring signal SEN increases to the voltage of reference signal REF2, comparator 534 output digit signals 1 are to the R input of set-reset flip-floop 522, thereby set-reset flip-floop 522 output digit signals 0 disconnect switch Q16.After switch Q16 disconnects, inductance L 1 electric discharge is to power to LED chain 312, and LED electric current 602 reduces gradually.If pulse width modulating signal PWM2 is digital signaling zero, be output as digital signaling zero with door 524, control switch Q16 disconnects, and LED electric current 602 reduces gradually.If pulse width modulating signal PWM2 keeps the state long enough of digital signaling zero, electric current 602 can be reduced to 0.Therefore, if pulse width modulating signal PWM2 is the first state, for example digital signal 1, and light adjusting controller 1008 is connected control switch Q16 under the effect of pulse signal 536, and when LED electric current 602 increases to maximum Imax, disconnects control switch Q16.If pulse width modulating signal PWM2 is the second state, digital signaling zero for example, light adjusting controller 1008 retentive control switch Q16 disconnect.As previously mentioned, the duty ratio of pulse width modulating signal PWM2 has determined the average current of LED chain 312.As shown in figure 12, if mains switch 304 is connected, the duty ratio of pulse width modulating signal PWM2 is along with the voltage of ramp signal RAMP1 increases and increases until duty ratio increases to 100% gradually.Therefore, the average current of LED chain 312 increases gradually, thereby the brightness of LED chain 312 also increases gradually.
Figure 14 shows that the circuit diagram of light source driving circuit 1400 according to an embodiment of the invention.Parts identical with Figure 10 label in Figure 14 have similar function.If the mains switch 304 being coupled between power supply and light source driving circuit 1400 is connected, light source driving circuit 1400 increases the brightness of light source gradually.
In one embodiment, light source driving circuit 1400 comprises electric power converter 310 and light adjusting controller 1408.Electric power converter 310 and power supply and 312 couplings of LED chain.Electric power converter 310 receives electric energy that power supplys provide and provides the electric energy after adjusting for LED chain 312.In the embodiment of Figure 14, electric power converter 310 is the step-down controllers that comprise inductance L 1, diode D4 and control switch Q16.In Figure 10, control switch Q16 can be positioned at light adjusting controller 1408 outsides.In other embodiments, control switch Q16 also can be integrated in light adjusting controller 1408 inside.Electric energy after the adjusting that the control switch Q16 adjustment electric power converter 310 that light adjusting controller 1408 is connected with LED chain 312 by control provides.In one embodiment, light adjusting controller 1408 is according to the flow through electric current of LED chain 312 of a ramp signal adjustment, makes the average current of LED chain 312 when being coupled in mains switch 304 between power supply and light source driving circuit 1400 and connecting increase to gradually preset value.
Light source driving circuit 1400 also comprises for AC-input voltage Vin being converted to the AC/DC converter 306 of VD Vout, and monitoring stream is through the current monitor 314 of LED chain 312 electric currents.In the embodiment of Figure 14, AC/DC converter 306 is the bridge rectifiers that consist of diode D1, D2, D7, D8, D10 and capacitor C 9.Current monitor 314 comprises current monitoring resistance R 5.
In the embodiment of Figure 14, light adjusting controller 1408 has port HV_GATE, VREF, ADJ, RT, VDD, CTRL, MON and GND.Port HV_GATE is coupled with switch Q27 by resistance R 3, for the conducting state of control switch Q27.Capacitor C 11 is coupled between port HV_GATE and ground, and for switch, Q27 provides grid voltage.Port VREF is by resistance R 20 and energy-storage units, and for example capacitor C 14 is coupled with ground.It is that capacitor C 14 charges to produce ramp signal RAMP2 that port VREF provides direct voltage.Port ADJ and capacitor C 14 couplings, receive ramp signal RAMP2.Port RT is by resistance R 7 and ground coupling, for determining the frequency of the pulse signal that light adjusting controller 1408 produces.Port VDD is coupled by diode D9 and switch Q27, is light adjusting controller 1408 power supplies.In one embodiment, be coupled in the energy-storage units between port VDD and ground, for example capacitor C 10 is light adjusting controller 1408 power supplies when mains switch 304 disconnects.In another embodiment, energy-storage units is integrated in light adjusting controller 1408 inside.Port GND is connected to the ground.Light adjusting controller 1408 is adjusted the electric energy of electric power converter 310 by controlling control switch Q16.
Figure 15 shows that the structural representation of the light adjusting controller 1408 in Figure 14.Parts identical with Figure 11 label in Figure 15 have similar function.Figure 15 describes in connection with Figure 14.
In the embodiment of Figure 15, light adjusting controller 1408 comprises pulse signal producer 504, startup and low pressure lock-in circuit 508 and comparator 1534.Startup and low pressure lock-in circuit 508 optionally start one or more parts of light adjusting controller 1408 inside according to the different electric energy situation of light adjusting controller 1408.In the embodiment of Figure 15, startup and low pressure lock-in circuit 508 comprise for the reference voltage generator 1505 of direct voltage is provided at port VREF.Pulse signal producer 504 produces pulse signal, for connecting control switch Q16.The current monitoring signal SEN that the ramp signal RAMP2 that comparator 1534 receives port ADJ and current monitoring resistance R 5 provide compares.Ramp signal RAMP2 is transferred into the end of oppisite phase of comparator 1106.Current monitoring signal SEN is transferred into the in-phase end of comparator 1106.The voltage of current monitoring signal SEN represents the size of current of the LED chain 312 of flowing through when switch Q27 and switch Q16 connection.In the embodiment of Figure 15, the voltage of ramp signal RAMP2 has determined the lowest high-current value Imax of LED chain 312.Zener diode ZD2 is coupled between port ADJ and ground, the voltage clamping to ramp signal RAMP2.
Figure 16 shows that the signal waveforms of light source driving circuit according to an embodiment of the invention, this light source driving circuit includes the light adjusting controller 1408 shown in Figure 15.Figure 16 shows electric current 602, pulse signal 536, the output V522 of set-reset flip-floop 522 and the conducting state of control switch Q16 of the LED chain 312 of flowing through.Figure 16 describes in connection with Figure 14 and Figure 15.
Pulse signal producer 504 produces pulse signal 536.In pulse signal 536, under the effect of each pulse, set-reset flip-floop 522 produces digital signal 1 at Q output.Set-reset flip-floop 522 produces digital signal 1 at Q output control switch Q16 is connected, and the electric current of the inductance L of flowing through 1 increases, and LED electric current 602 increases.When LED electric current 602 increases to maximum Imax, illustrate that the voltage of current monitoring signal SEN increases to the voltage of ramp signal RAMP2, comparator 1534 output digit signals 1 are to the R input of set-reset flip-floop 522, thereby set-reset flip-floop 522 output digit signals 0 disconnect switch Q16.After switch Q16 disconnects, inductance L 1 electric discharge is to 312 power supplies of LED chain, and LED electric current 602 reduces gradually.By adjusting the voltage of ramp signal RAMP2, average current and the brightness of LED chain 312 are also adjusted accordingly.
When mains switch 304, connect, light adjusting controller 1408 receives electric energy by port VDD.If the voltage of port VDD is greater than predeterminated voltage value, light adjusting controller 1408 is at port VREF output dc voltage.Capacitor C 14 is charged under the effect of this direct voltage, and the voltage at its two ends (being ramp signal RAMP2) increases.Therefore, if mains switch 304 is connected, the maximum Imax of LED electric current increases to preset maximum value gradually, and the average current of LED chain 312 also increases gradually.
Figure 17 shows that the method flow diagram 1700 that according to an embodiment of the invention light source is carried out controlling electric energy.Figure 17 is described in connection with Figure 10 and Figure 14.
In step 1702, utilize electric power converter, for example electric power converter 310, and the electric energy after the adjusting providing is to light source, and for example LED chain 312 is powered.
In step 1704, if be coupled in the mains switch between power supply and electric power converter 310, for example mains switch 304 is connected, and increases the voltage of ramp signal.
In step 1706, along with the voltage increase of ramp signal, increase the average current of light source, until average current increases to preset value.
In one embodiment, by relatively ramp signal and sawtooth signal produce pulse width modulating signal.The duty ratio of this pulse width modulating signal is determined by the voltage of ramp signal.This pulse width modulating signal is controlled the control switch of connecting with light source, control switch Q16 for example, thereby the average current of adjustment light source.Produce in addition pulse signal.If this pulse width modulating signal is the first state, control switch is connected under the effect of pulse signal, when indication flow through the current monitoring signal of electric current of light source while increasing to reference signal control switch disconnect.This reference signal determines the lowest high-current value of light source.If this pulse width modulating signal is the second state, control switch disconnects.
In another embodiment, ramp signal determines the lowest high-current value of light source.By ramp signal is compared to produce control signal with indicating the current monitoring signal of the electric current of the light source of flowing through, and utilize this control signal to control control switch.Produce in addition pulse signal.Control switch is connected under the effect of pulse signal, and when current monitoring signal increases to ramp signal, control switch disconnects.
As previously mentioned, the present invention discloses a kind of light source driving circuit.If the mains switch being coupled between power supply and this light source driving circuit is connected, this light source driving circuit increases the brightness of light source gradually, thereby avoids jump in brightness, for user provides more comfortable user, experiences.
Figure 18 shows that the schematic diagram of light source driving circuit 1800 according to an embodiment of the invention.In one embodiment, light source driving circuit 1800 adopts the isolated DC/direct current transducer 1807 that comprises transformer 1808.Transformer 1808 comprises that former limit winding and secondary winding realize the isolation between the secondary circuit that is coupled in the former limit circuit of former limit winding and is coupled in secondary winding, thereby suppresses high-frequency electromagnetic noise.In one embodiment, be coupled in mains switch 1804 between AC power 1802 and light source driving circuit 1800 for being optionally switched on or switched off the connection between AC power 1802 and light source driving circuit 1800.Figure 19 shows the example of mains switch 1804 according to an embodiment of the invention.In one embodiment, mains switch 1804 can be the mains switch being placed on metope.The handle 1980 that is placed in the mains switch on metope by switching, user can control the conducting state of mains switch 1804, for example, disconnect or the switch that switches on power.
Please refer again to Figure 18, light source driving circuit 1800 also comprises AC/DC converter 1806, on-off controller 1810, current detector 1814, light adjusting controller 1816 and optical coupler 1818.AC/DC converter 1806 is by the input ac voltage V from AC power 1802
iNbe converted to direct voltage V
dC.Isolated DC/direct current transducer 1807 is coupled in AC/DC converter 1806 and light source, and for example LED chain 1812, between.Isolated DC/direct current transducer 1807 receives direct voltage V
dCand provide the output voltage V after adjusting for LED chain 1812
oUT.On-off controller 1810 is coupled between the former limit winding of optical coupler 1818 and transformer 1808.On-off controller 1810 receives the electric current I of indicating the LED chain 1812 of flowing through from optical coupler 1818
lEDthe feedback signal CFB of desired value, and according to feedback signal CFB, control the input electric energy of former limit winding.Above-mentioned electric current I
lEDdesired value represent electric current I
lEDthe desired value reaching after adjustment.Specifically, on-off controller 1810 produces and drives signal DRV according to feedback signal CFB.Drive signal DRV to control the input electric energy of former limit winding, thereby regulate the output voltage V of isolated DC/direct current transducer 1807
oUT.Current detector 1814 produces the electric current I of indicating the LED chain 1812 of flowing through
lEDcurrent monitoring signal SEN.Light adjusting controller 1816 is coupled between optical coupler 1818 and the secondary winding of transformer 1808.Light adjusting controller 1816 receives 1804 actions of indication mains switches, for example, disconnect action, switch monitor signal TS, and according to switch monitor signal TS, by adjusting feedback signal CFB, regulate the output voltage V of isolated DC/direct current transducer 1807
oUT.
In one embodiment, light adjusting controller 1816 works in analog dimming mode, regulates the electric energy of LED chain 1812 by adjusting the size of reference signal.This reference signal is indicated the electric current I of the LED chain 1812 of flowing through
lEDthe desired value of mean value.In another embodiment, light adjusting controller 1816 works in pulse light modulation pattern, recently adjusts the electric energy of LED chain 1812 by adjusting the duty of a pulse width modulating signal (being pwm signal).By adjusting the electric energy of LED chain 1812, the brightness of LED chain 1812 can access accordingly and adjust.
Figure 20 shows that the circuit diagram of light source driving circuit 2000 according to an embodiment of the invention.Figure 20 is described in connection with Figure 18.Parts identical with Figure 18 label in Figure 20 have similar function, are not repeated in this description for simplicity's sake at this.
In the embodiment shown in Figure 20, AC/DC converter 1806 comprises rectifier and capacitor C 1.Rectifier can be the bridge rectifier that comprises diode D1, diode D2, diode D7 and diode D8.Current detector 1814 comprises current sense resistance R 5.
The input electric energy that isolated DC/direct current transducer 1807 receives from AC/DC converter 1806, and be light source, for example LED chain 1812, and the output voltage V after adjusting is provided
oUT.In the embodiment shown in Figure 20, isolated DC/direct current transducer 1807 comprises transformer 1808, control switch Q1, diode D4 and capacitor C 6.Transformer 1808 comprises for receiving former limit winding 2004 from the input electric energy of AC/DC converter 1806, being used to LED chain 1812 that secondary winding 2006 and the magnetic core 2024 of output electric energy are provided.Transformer 1808 also comprises the auxiliary winding 2008 that is used to on-off controller 1810 that electric energy is provided.For the purpose of illustration, three windings have been illustrated in the embodiment shown in Figure 20.Yet transformer 1808 can comprise the winding of varying number.In the embodiment shown in Figure 20, the control switch Q1 that is coupled in former limit winding 2004 is positioned at the outside of on-off controller 1810.In other embodiment, control switch Q1 also can be integrated in the inside of on-off controller 1810.
On-off controller 1810 is coupled in former limit winding 2004 and the auxiliary winding 2008 of transformer 1808.On-off controller 1810 can be flyback PWM controller, optionally connects the control switch Q1 connecting with former limit winding 2004 for generation of pwm signal, and for recently adjust the output electric energy of transformer 1808 by adjusting the duty of pwm signal.For example and and unrestricted, the port of on-off controller 1810 comprises: FB, GATE, CS, RT, VDD and GND.Port FB is for receiving the electric current I of indicating the LED chain 1812 of flowing through from optical coupler 1818
lEDthe feedback signal CFB of desired value.For instance, optical coupler 1818 comprises LED2016 and phototransistor 2012.Port FB is from phototransistor 2012 receiving feedback signals CFB.
Port CS receives the monitor signal LPSEN of the electric current of indicating the former limit winding 2004 of flowing through.On-off controller 1810 receiving feedback signals CFB and monitor signal LPSEN, and generation drives signal DRV to control control switch Q1 on port GATE, thus regulate the output voltage V of isolated DC/direct current transducer 1807
oUT.In one embodiment, driving signal DRV is pwm signal.Port RT is for determining to drive the frequency of signal DRV.
According to feedback signal CFB and monitor signal LPSEN, port GATE provides the conducting state that drives signal DRV to control control switch Q1, for example ON/OFF state.Specifically, in one embodiment, when the voltage of monitor signal LPSEN is greater than the voltage of feedback signal CFB, the electric current of the former limit winding 2004 that represents to flow through is greater than the electric current I of the LED chain 1812 of flowing through
lEDdesired value, on-off controller 1810 reduces the duty ratio that drives signal DRV, vice versa.In one embodiment, if drive signal DRV, be the first state, for example logic is high, and control switch Q1 connects, the electric current former limit winding 2004 of flowing through, and magnetic core 2024 starts energy storage.If driving signal DRV is the second state, logic low for example, control switch Q1 disconnects, and be coupled in the diode D4 forward bias of secondary winding 2006 so that the energy being stored in magnetic core 2024 is released into capacitor C 6 and LED chain 1812 through secondary winding 2006, thereby adjust electric energy and the brightness of LED chain 1812.
Port VDD is coupled to AC/DC converter 1806 and auxiliary winding 2008.In one embodiment, energy-storage units, as capacitor C 5, is connected between port VDD and ground.Energy-storage units is on-off controller 1810 power supplies when mains switch 1804 disconnects.Port GND is connected to the ground.
Port CLK/OVP is coupled in secondary winding 2006, is coupled in the switch monitor signal TS of the action of the mains switch 1804 between AC power 1802 and AC/DC converter 1806 for receiving indication.In one embodiment, after mains switch 1804 is connected, switch monitor signal TS has positive negative pulse stuffing waveform.Specifically, when the voltage of the secondary winding 2006 of transformer 1808 is increased to the rising threshold value of transformer 1808, switch monitor signal TS becomes positive voltage level from negative voltage level.When the lower voltage of the secondary winding 2006 of transformer 1808 is during to the falling-threshold value of transformer 1808, switch monitor signal TS becomes negative voltage level from positive voltage level.In one embodiment, after mains switch 1804 disconnects, switch monitor signal TS is zero.The voltage of light adjusting controller 1816 monitoring switch monitor signal TS is with the action of monitoring mains switch 1804 and detect when conducting/disconnection of mains switch 1804.In one embodiment, light adjusting controller 1816 also comprises that overvoltage protection (Over-Voltage Protection, OVP) circuit avoids the overpressure situation of LED chain 1812.
Port FB is coupled in current sense resistance R 5, for receiving the electric current I of indicating the LED chain 1812 of flowing through
lEDcurrent monitoring signal SEN.Port COMP for generation of compensating signal to control the control switch Q1 connect with the former limit winding 2004 of transformer 1808, thereby according to the action of mains switch 1804 and switch monitor signal TS, regulate the electric energy of LED chain 1812.Specifically, the compensating signal on port COMP is for adjusting the received feedback signal CFB of on-off controller 1810.
Port RT is used for arranging predetermined amount of time.In one embodiment, after predetermined amount of time expires, the counter in replacement light adjusting controller 1816.Port VDD is used to light adjusting controller 1816 that electric energy is provided.In one embodiment, energy-storage units, as capacitor C 6, is connected between port VDD and ground.Energy-storage units is light adjusting controller 1816 power supplies when mains switch 1804 disconnects.Port GND is connected to the ground.
Advantageously, the disconnection action according to mains switch 1804 in the circuit of former limit can utilize the light adjusting controller 1816 in secondary circuit to carry out feedback loop control after mains switch 1804 is connected again, thus by the brightness adjustment of LED chain 1812 to desired value.
Figure 21 is depicted as the structural representation of the light adjusting controller 1816 in Figure 20.Figure 21 is described in connection with Figure 20.Parts identical with Figure 20 label in Figure 21 have similar function, are not repeated in this description for simplicity's sake at this.
As mentioned above, dim signal can be for having the analog REF3 of variable voltage.Digital to analog converter 2107 can be adjusted according to the count value of counter 2111 voltage of reference signal REF3.In the embodiment shown in Figure 21, the voltage of the reference signal REF3 electric current I of LED chain 1812 that determines to flow through
lEDthe desired value of mean value.Thus, can adjust by adjusting reference signal REF3 the brightness of LED chain 1812.
In one embodiment, the count value increase of counter 2111 makes digital to analog converter 2107 turn down the voltage of reference signal REF3.For example, if count value is 0, the voltage that digital to analog converter 2107 is adjusted reference signal REF3 is V6.If trigger monitoring means 2131, monitor the disconnection action of mains switch 1804 at port CLK/OVP, thereby make count value be increased to 1, the voltage that digital to analog converter 2107 is adjusted reference signal REF3 is V7, and V7 is less than V6.In another embodiment, the count value increase of counter 2111 makes digital to analog converter 2107 heighten the voltage of reference signal REF3.
In one embodiment, when the count value of counter 2111 reaches maximum, count value is set to predetermined value again, and for example 0.By way of example, if counter 2111 is two digit counters, count value will be increased to 1,2,3 successively since 0, then after four opening operations of mains switch 1804, get back to 0.Accordingly, the brightness of LED chain 1812 is adjusted to the second level successively from the first order, the third level, and the fourth stage, then gets back to again the first order.Dimmer 2133 also can comprise the timer 2109 that is coupled in counter 2111.When triggering monitoring means 2131 when port CLK/OVP monitors the disconnection action of mains switch 1804, timer 2109 starts timing.If mains switch 1804 continues to disconnect, surpass predetermined amount of time, for example, surpass 3 seconds, the count value of counter 2111 is set to predetermined value again, for example, set to 0.This predetermined amount of time is to be determined by the voltage on the port RT of light adjusting controller 1816.Advantageously, if a plurality of LED light source drive circuit is to be controlled by a common wall-board switch, utilize the timer 2109 can each LED light source of Synchronization Control.
In one embodiment, light adjusting controller 1816 works in analog dimming mode, wherein operational amplifier 2105 dim signals (being reference signal REF3) and indicate the electric current I of the LED chain 1812 of flowing through relatively
lEDcurrent monitoring signal SEN, and produce compensating signal and adjust feedback signal CFB.When the voltage of current monitoring signal SEN is greater than the voltage of reference signal REF3, the electric current I of the LED chain 1812 that represents to flow through
lEDbe greater than the desired value of the mean value of the electric current being determined by reference signal REF3, operational amplifier 2105 is adjusted compensating signal to reduce the voltage on port COMP.Accordingly, the electric current of the optical coupler 1818 of flowing through increases, the lower voltage of the feedback signal CFB on the port FB of on-off controller 1810.Therefore, on-off controller 1810 reduces the duty ratio that drives signal DRV according to feedback signal CFB, thereby reduces the output electric energy of isolated DC/direct current transducer 1807.Similarly, when the voltage of current monitoring signal SEN is less than the voltage of reference signal REF3, the electric current I of the LED chain 1812 that represents to flow through
lEDbe less than the desired value of the current average being determined by reference signal REF3, operational amplifier 2105 is adjusted compensating signal to increase the voltage on port COMP.Accordingly, the voltage of the feedback signal CFB on the port FB of on-off controller 1810 increases.Therefore, on-off controller 1810 improves the duty ratio that drives signal DRV according to feedback signal CFB, thereby increases the output electric energy of isolated DC/direct current transducer 1807.
Light adjusting controller 1816 also can comprise or door 2103.Or door 2103 receives the overvoltage signal being produced by OVP circuit 2115 and the shutoff signal being produced by counter 2111.The cut-out of this shutoff signal indication LED chain 1812.Specifically, when the voltage of switch monitor signal TS surpasses predetermined safe voltage, OVP circuit 2115 produces overvoltage signal.In one embodiment, when light adjusting controller 1816 detects the lasting disconnection of mains switch 1804 over predetermined amount of time according to switch monitor signal TS, for example, surpass 3 seconds, counter 2111 produces shutoff signals.In addition, the count value of counter 2111 is reset as predetermined value, for example, set to 0.Shutoff signal also can be produced by light modulation judge module 2113 or other unit, and is not limited to the setting shown in Figure 21.Or door 2103 carrys out turn on-switch 2121 according to overvoltage signal or shutoff signal output control signal.Specifically, according to the overvoltage signal of the overpressure situation of indication LED chain 1812, the shutoff signal of the cut-out of for example logical one, or indication LED chain 1812, logical one for example, light adjusting controller 1816 by the voltage on port COMP be pulled down to (pull to zero).Therefore, the electric current of the optical coupler 1818 of flowing through increases to maximum, and the voltage of feedback signal CFB is down to minimum value.Therefore, on-off controller 1810 stops producing driving signal DRV.In one embodiment, when LED chain 1812 is reworked and recover luminous, overvoltage signal and shutoff signal are all logical zero.Thereby switch 2121 is cut off operational amplifier 2105 and adjusts the voltage on port COMP according to reference signal REF3 and current monitoring signal SEN.
Figure 22 is depicted as the signal waveform schematic diagram under analog dimming mode, comprising the ON/OFF state of mains switch 1804, the voltage on the port VDD of on-off controller 1810, drive signal DRV, switch monitor signal TS, output voltage V
oUTand reference signal REF3.Figure 22 is described in connection with Figure 20 and Figure 21.
In operation, at time point t0, mains switch 1804 is connected.At time point t1, the voltage on the port VDD of on-off controller 1810 increases to and enables threshold value V
sTH1, 13V for example, on-off controller 1810 produces and drives signal DRV.Once mains switch 1804 disconnects, the voltage on the port VDD of on-off controller 1810 starts to decline.At time point t2, the voltage drop on the port VDD of on-off controller 1810 is to forbidden energy threshold value V
sTH2, 9V for example, on-off controller 1810 stops producing and drives signal DRV.Although Figure 22 does not illustrate, drive the duty ratio of signal DRV to be adjusted according to the feedback signal CFB of on-off controller 1810.
In addition,, at time point t1, t3, t5 and t7, the voltage on the port VDD of on-off controller 1810 increases to and enables threshold value V
sTH1, switch monitor signal TS becomes positive negative pulse stuffing waveform from zero.At time point t2, t4 and t6, the voltage drop on the port VDD of on-off controller 1810 is to forbidden energy threshold value V
sTH2, switch monitor signal TS is from the vanishing of positive negative pulse stuffing waveform.By monitoring switch monitor signal TS, light adjusting controller 1816 can be detected the disconnection of mains switch 1804 and move and adjust reference signal REF3.
In the embodiment shown in Figure 22, reference signal REF3 has three kinds of voltage: 150mV, 100mV and 30mV.At time point t1, switch monitor signal TS detects mains switch 1804 and connects.Reference signal REF3 has the first level, for example 150mV.At time point t2, switch monitor signal TS detects mains switch 1804 disconnections and reference signal REF3 is adjusted to second electrical level from the first level, for example 100mV.In the embodiment shown in Figure 22, between time point t2 and t3 interval greater than predetermined amount of time, t3-t2>3 second for example, represent mains switch 1804 continue to disconnect surpass predetermined amount of time after connection.Therefore,, during t3 to t4, reference signal REF3 is set to predetermined level, for example 150mV again.At time point t4, switch monitor signal TS detects mains switch 1804 disconnections and reference signal REF3 is adjusted to second electrical level from the first level.The time interval between time point t4 and t5 is less than predetermined amount of time, t5-t4<3 second for example, represents that mains switch is shorter than predetermined amount of time 1804 opening times.Therefore,, during t5 to t6, reference signal REF3 maintains second electrical level.At time point t6, switch monitor signal TS detects mains switch 1804 disconnections and reference signal REF3 is adjusted to the 3rd level, for example 30mV from second electrical level.Accordingly, the brightness of LED chain 1812 is adjusted according to reference signal REF3.
Figure 23 is depicted as the schematic diagram of light source driving circuit 2300 according to an embodiment of the invention.Figure 23 is described in connection with Figure 20.Parts identical with Figure 20 label in Figure 23 have similar function, are not repeated in this description for simplicity's sake at this.Except light adjusting controller 2316, the schematic diagram of the light source driving circuit 2300 shown in Figure 23 is similar to the schematic diagram of the light source driving circuit 2000 shown in Figure 20.In the embodiment shown in Figure 23, the port of light adjusting controller 2316 comprises: CLK/OVP, FB, COMP, PWM, VDD and GND.Port CLK/OVP receives the switch monitor signal TS of the action of indication mains switch 1804.
Port FB receives the electric current I of indicating the LED chain 1812 of flowing through
lEDcurrent monitoring signal SEN.According to current monitoring signal SEN and switch monitor signal TS, at port COMP, produce compensating signal.Indicate the electric current I of the LED chain 1812 of flowing through
lEDthe feedback signal CFB of desired value can according to compensating signal, be adjusted via optical coupler 1818.Therefore, drive duty ratio, the output electric energy of isolated DC/direct current transducer 1807 and the brightness of LED chain 1812 of signal DRV to obtain corresponding adjustment.
Port PWM is coupled in control switch Q2.Control switch Q2 connects with LED chain 1812, and is connected to ground by current monitoring resistance R 5.Light adjusting controller 2316 is controlled the conducting state of control switch Q2 by the pwm signal DRV2 on port PWM, ON/OFF state for example, and by adjusting the duty ratio of pwm signal DRV2, the electric current I of light adjusting controller 2316 capable of regulating feedback signal CFB and the LED chain 1812 of flowing through
lED.By way of example, if pwm signal DRV2 has 100% duty ratio, LED chain 1812 has high-high brightness.If the duty ratio of pwm signal DRV2 is less than 100%, the brightness of LED chain 1812 is lower than high-high brightness.For example and and unrestricted, the duty ratio of pwm signal DRV2 can be 100%, 75%, 50% and 25%, LED chain 1812 can have respectively 100% brightness, 75% brightness, 50% brightness and 25% brightness accordingly.
Port VDD is used to light adjusting controller 2316 that electric energy is provided.In one embodiment, energy-storage units, as capacitor C 6, is connected between port VDD and ground.Energy-storage units is light adjusting controller 2316 power supplies when mains switch 1804 disconnects.Port GND is connected to the ground.
Advantageously, the disconnection action according to mains switch 1804 in the circuit of former limit can utilize the light adjusting controller 2316 in secondary circuit to carry out feedback loop control after mains switch 1804 is connected again, thus by the brightness adjustment of LED chain 1812 to desired value.
Figure 24 is depicted as the structural representation of the light adjusting controller 2316 in Figure 23.Figure 24 is described in connection with Figure 23.Parts identical with Figure 23 label with Figure 21 in Figure 24 have similar function, are not repeated in this description for simplicity's sake at this.
Except dimmer 2433 and operational amplifier 2405, the structure of the light adjusting controller 2316 shown in Figure 24 is similar to the structure of the light adjusting controller 1816 shown in Figure 21.In the embodiment shown in Figure 24, dimmer 2433 comprises the counter 2411 that is coupled in triggering monitoring means 2131 and the digital to analog converter 2407 that is coupled in counter 2111.The driving signal 2420 that counter 2411 is produced by triggering monitoring means 2131 drives.Counter 2411 is for calculating the action frequency of mains switch 1804.Specifically, in one embodiment, after mains switch 1804 disconnects, switch monitor signal TS is zero.In one embodiment, when detecting no-voltage on port CLK/OVP, trigger monitoring means 2131 and produce driving signal 2420.The count value of counter 2411 according to driving signal 2420 to change, for example, adds 1.Digital to analog converter 2407 reads count value from counter 2411, and produces dim signal 2408 according to count value.Dimmer 2433 also can comprise the timer 2409 that is coupled in counter 2411, and it is similar to the timer 2109 shown in Figure 21.
Dimmer 2433 also comprises the PWM generator 2409 that is coupled in digital to analog converter 2407.In one embodiment, light adjusting controller 2316 works in pulse light modulation pattern, and wherein PWM generator 2409 produces pwm signal DRV2 according to dim signal 2408.The duty ratio of pwm signal DRV2 is to be determined by dim signal 2408, for example, can be 100%, 75%, 50% and 25%.Pwm signal DRV2 adjusts feedback signal CFB and controls the control switch Q2 connecting with LED chain 1812.Specifically, operational amplifier 2405 received current monitor signal SEN and reference signal REF4, and produce compensating signal on port COMP.In the embodiment shown in Figure 24, reference signal REF4 is the direct current signal with essence constant voltage.When pwm signal DRV2 is the first state, for example logical one, control switch Q2 connection and switch 2423 disconnections.Therefore, operational amplifier 2405 produces compensating signal according to current monitoring signal SEN and reference signal REF4.This compensating signal can be adjusted the electric current I of indicating the LED chain 1812 of flowing through via optical coupler 1818
lEDthe feedback signal CFB of desired value.When pwm signal DRV2 is the second state, for example logical zero, control switch Q2 disconnection and switch 2423 connections.Therefore, the voltage of compensating signal is pulled down to ground.The voltage of feedback signal CFB is down to minimum value, and on-off controller 1810 stops producing driving signal DRV.Therefore, dim signal 2408 can be used for adjusting feedback signal CFB, adjusts the brightness of LED chain 1812 thereupon.
Advantageously, the disconnection action according to mains switch 1804 in the circuit of former limit can utilize the light adjusting controller 2316 in secondary circuit to carry out feedback loop control after mains switch 1804 is connected again, thus by the brightness adjustment of LED chain 1812 to desired value.
Figure 25 is depicted as the signal waveform schematic diagram under pulse light modulation pattern, comprising the ON/OFF state of mains switch 1804, the voltage on the port VDD of on-off controller 1810, drive signal DRV, switch monitor signal TS, output voltage V
oUTand the duty ratio of pwm signal DRV2.Figure 25 is described in connection with Figure 23 and Figure 24.
Voltage on the port VDD of the ON/OFF state of mains switch 1804, on-off controller 1810, driving signal DRV, switch monitor signal TS and output voltage V
oUTbetween relation object be similar to the relation shown in Figure 22.In the analog dimming mode shown in Figure 22, by adjusting reference signal REF3, can adjust accordingly output voltage V
oUTthereby, adjust the brightness of LED chain 1812.In the pulse light modulation pattern shown in Figure 25, at time point t0, mains switch 1804 is connected.At time point t1, switch monitor signal TS detects mains switch 1804 and connects, and pwm signal DRV2 has the first duty ratio, and for example 100%.At time point t2, switch monitor signal TS detects mains switch 1804 and disconnects.In the embodiment shown in Figure 25, between time point t2 and t3 interval greater than predetermined amount of time, t3-t2>3 second for example, indication mains switch 1804 continue to disconnect surpass predetermined amount of time after connection.Therefore, during t3 to t4, the duty ratio of pwm signal DRV2 is set to predetermined value again, and for example 100%.At time point t4, switch monitor signal TS detects mains switch 1804 and disconnects.The time interval between time point t4 and t5 is less than predetermined amount of time, and t5-t4<3 second for example, indication mains switch is shorter than predetermined amount of time 1804 opening times.Therefore, during t5 to t6, the duty ratio of pwm signal DRV2 is adjusted to the second duty ratio, and for example 50%.Similarly, at time point t7, the duty ratio of pwm signal DRV2 is adjusted to the 3rd duty ratio, and for example 25%.By adjusting the duty ratio of pwm signal DRV2, can adjust accordingly output voltage V
oUTthereby, adjust the brightness of LED chain 1812.
Figure 26 is depicted as according to an embodiment of the invention to light source, and LED light source for example carries out the method flow diagram 2600 of controlling electric energy.Figure 26 is described in connection with Figure 20, Figure 21, Figure 23 and Figure 24.
In step 2602, DC-DC converter, for example, comprise and the isolated DC/direct current transducer 1807 of transformer 1806 provide the electric energy after adjusting to power to LED light source, for example, LED chain 1812 is powered.
In step 2604, receive the feedback signal CFB of the desired value of the electric current of indicating the light source of flowing through, for example by on-off controller 1810, received.
In step 2606, receiving key monitor signal TS, for example the light adjusting controller in secondary circuit 1816 receives, and this switch monitor signal TS indicates the action of mains switch in the circuit of former limit, for example action of mains switch 1804.
In step 2608, according to switch monitor signal TS, produce dim signal.
In step 2610, according to dim signal, adjust feedback signal, and produce and drive signal DRV according to the feedback signal after adjusting, with control with DC-DC converter in the switch of former limit windings in series of transformer, the output electric energy of for example control switch Q1, and then adjusting DC-DC converter.In an embodiment who adopts analog dimming mode, by the flow through current monitoring signal SEN of source current of relatively dim signal and indication, regulate the output electric energy of DC-DC converter.At another, adopt in the embodiment of pulse light modulation pattern, by adjust the duty of pulse width modulating signal according to dim signal, recently regulate the output electric energy of DC-DC converter.
As previously mentioned, the present invention discloses a kind of light source driving circuit, this light source driving circuit is adjusted the electric energy of light source according to the switch monitor signal of indication mains switch action, and mains switch can be fixing mains switch on the wall.The electric energy of this light source is provided by isolated DC/direct current transducer, and is adjusted by the switch of the former limit windings in series of transformer in control and isolated DC/direct current transducer by light adjusting controller.
User can pass through the action to common power switch, as disconnected action, regulates the brightness of light source, and needn't use extra device, for example, without the custom-designed switch with light modulation button, thereby saves cost.
Wording and expression in this use are all illustrative rather than definitive thereof, use these wording and do not express any equivalent of the characteristic in this diagram and description (or part equivalent) is got rid of outside invention scope, may have various modifications within the scope of the claims.Other modification, variant and alternative also may exist.Therefore, claim is intended to contain all these type of equivalents.
Claims (16)
1. LED source is carried out to a drive circuit for controlling electric energy, it is characterized in that, described drive circuit comprises:
Transformer, described transformer comprises receiving from the former limit winding of the input electric energy of AC/DC converter with for described LED source provides the secondary winding of output electric energy;
Be connected in the on-off controller between optical coupler and described former limit winding, for receive the feedback signal of the desired value of the electric current of indicating the described LED source of flowing through from described optical coupler, and according to described feedback signal, control the input electric energy of described former limit winding; And
The light adjusting controller being connected with described secondary winding, described light adjusting controller receives the switch monitor signal and the current monitoring signal of indicating the electric current of the described LED source of flowing through of the action of indication mains switch, and produce compensating signal according to described switch monitor signal and described current monitoring signal, described compensating signal is adjusted described feedback signal via described optical coupler, to regulate the output electric energy of described transformer by adjusting described feedback signal, wherein said mains switch is connected between AC power and described AC/DC converter
Wherein, described light adjusting controller comprises:
Trigger monitoring means, for receiving described switch monitor signal and producing and drive signal according to the action of described mains switch; And
The dimmer being connected with described triggering monitoring means, for producing dim signal to adjust described compensating signal according to described driving signal,
Wherein, described light adjusting controller works in pulse light modulation pattern, under described pulse light modulation pattern, according to described dim signal, produce the first pulse width modulating signal, the duty ratio of described the first pulse width modulating signal is determined by described dim signal, and described the first pulse width modulating signal is adjusted described compensating signal and controlled the second switch of connecting with described LED source.
2. drive circuit according to claim 1, is characterized in that, described LED source is light-emitting diode chain.
3. drive circuit according to claim 1, is characterized in that, the action of described mains switch comprises the described mains switch of disconnection.
4. drive circuit according to claim 1, is characterized in that, described transformer is also included as the auxiliary winding that described on-off controller provides electric energy.
5. drive circuit according to claim 1, it is characterized in that, described on-off controller produces the second pulse width modulating signal and optionally connects the control switch with described former limit windings in series, and by adjusting the duty of described the second pulse width modulating signal, recently adjusts the output electric energy of described transformer.
6. drive circuit according to claim 1, is characterized in that, described light adjusting controller is monitored the voltage of described switch monitor signal to monitor the action of described mains switch.
7. drive circuit according to claim 1, is characterized in that, described dimmer comprises:
Counter by described drive; And
The digital to analog converter being connected with described counter, for producing described dim signal according to the count value of described counter.
8. drive circuit according to claim 7, is characterized in that, if described mains switch continue to disconnect surpasses predetermined amount of time, and the described light adjusting controller described counter of resetting.
9. a light adjusting controller, is characterized in that, described light adjusting controller is connected with the secondary winding of transformer, and described light adjusting controller is controlled from AC/DC converter the electric energy to LED source, and described light adjusting controller comprises:
Switch monitoring port, for receiving the switch monitor signal of the action of indication mains switch, wherein said mains switch is connected between AC power and described AC/DC converter;
Current monitoring port, for receiving the current monitoring signal of the electric current of indicating the described LED source of flowing through;
Compensation port, for producing compensating signal according to described switch monitor signal and described current monitoring signal, described compensating signal is via the flow through feedback signal of desired value of electric current of described LED source of optical coupler adjustment indication, thereby by adjusting described feedback signal, control the control switch with the former limit windings in series of described transformer, to adjust the electric energy of described LED source;
Trigger monitoring means, for receiving described switch monitor signal from described switch monitoring port and producing and drive signal according to the action of described mains switch; And
The dimmer being connected with described triggering monitoring means, for producing dim signal to adjust described compensating signal according to described driving signal,
Wherein, described light adjusting controller works in pulse light modulation pattern, under described pulse light modulation pattern, according to described dim signal, produce pulse width modulating signal, the duty ratio of described pulse width modulating signal is determined by described dim signal, and described pulse width modulating signal is adjusted described compensating signal and controlled the second switch of connecting with described LED source.
10. light adjusting controller according to claim 9, is characterized in that, the action of described mains switch comprises the described mains switch of disconnection.
11. light adjusting controllers according to claim 9, is characterized in that, described switch monitoring port is monitored the voltage of described switch monitor signal to monitor the action of described mains switch.
12. light adjusting controllers according to claim 9, is characterized in that, according to the overvoltage signal of the overpressure situation of the described LED source of indication, described light adjusting controller is pulled down to ground by the voltage on described compensation port.
13. light adjusting controllers according to claim 9, is characterized in that, described light adjusting controller also comprises:
Counter by described drive; And
The digital to analog converter being connected with described counter, for producing described dim signal according to the count value of described counter.
14. light adjusting controllers according to claim 13, is characterized in that, if described mains switch continue to disconnect surpasses predetermined amount of time, and the described light adjusting controller described counter of resetting.
15. 1 kinds of methods of LED source being carried out to controlling electric energy, is characterized in that, described method comprises:
Transformer provides the electric energy after adjusting to power to described LED source;
Receive the feedback signal of the desired value of the electric current of indicating the described LED source of flowing through;
Receive the switch monitor signal of the action of mains switch in the circuit of the former limit of indication;
Receive the current monitoring signal of the electric current of indicating the described LED source of flowing through;
According to described switch monitor signal, produce dim signal;
According to described dim signal and described current monitoring signal, produce compensating signal; And
According to described compensating signal, adjust described feedback signal, to adjust the output electric energy of described transformer,
Wherein, according to the step of described dim signal and described current monitoring signal generation compensating signal, comprise:
In the situation that adopting pulse light modulation pattern, according to described dim signal, produce pulse width modulating signal; And
According to described pulse width modulating signal, adjust described compensating signal.
16. methods according to claim 15, is characterized in that, the action of described mains switch comprises the described mains switch of disconnection.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110447599.XA CN102548143B (en) | 2011-12-28 | 2011-12-28 | Drive circuit, dimmer controller and method for electrically controlling light-emitting diode (LED) light source |
| US13/369,620 US9030122B2 (en) | 2008-12-12 | 2012-02-09 | Circuits and methods for driving LED light sources |
| IN931DE2012 IN2012DE00931A (en) | 2011-12-28 | 2012-03-28 | |
| JP2012104480A JP2013140931A (en) | 2011-12-28 | 2012-05-01 | Circuits and methods for driving led light sources |
| EP12180381.1A EP2611263A3 (en) | 2011-12-28 | 2012-08-14 | Circuits and methods for driving LED light sources |
| TW101141648A TWI568309B (en) | 2011-12-28 | 2012-11-08 | Driving circuit, dimming controller and control methods for light source |
| BRBR102012033492-5A BR102012033492A2 (en) | 2011-12-28 | 2012-12-28 | Circuits and Methods for Triggering LED Light Sources |
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| CN201110447599.XA CN102548143B (en) | 2011-12-28 | 2011-12-28 | Drive circuit, dimmer controller and method for electrically controlling light-emitting diode (LED) light source |
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| Publication Number | Publication Date |
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| CN102548143A CN102548143A (en) | 2012-07-04 |
| CN102548143B true CN102548143B (en) | 2014-03-12 |
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| CN201110447599.XA Expired - Fee Related CN102548143B (en) | 2008-12-12 | 2011-12-28 | Drive circuit, dimmer controller and method for electrically controlling light-emitting diode (LED) light source |
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| TWI573379B (en) * | 2015-08-25 | 2017-03-01 | 群光電能科技股份有限公司 | Power supplying device |
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Also Published As
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| CN102548143A (en) | 2012-07-04 |
| TW201328418A (en) | 2013-07-01 |
| TWI568309B (en) | 2017-01-21 |
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