TWI478625B - Dimming controllers, driving circuits and driving methods for driving light source - Google Patents

Description

Dimming controller, light source driving circuit, and light source driving method

The invention relates to a driving circuit, a controller and a driving method, in particular to a circuit, a controller and a method for driving a light source.

In recent years, light sources such as light-emitting diodes (LEDs) have been improved through advances in materials and process technology. LEDs are characterized by high efficiency, long life and bright colors, and can be used in automobiles, computers, telecommunications, military and daily necessities. For example, LED lights can be used as an illumination source instead of conventional incandescent lamps.

FIG. 1 shows a schematic diagram of a conventional LED driving circuit 100. The LED drive circuit 100 uses an LED string 106 as a light source. LED chain 106 includes a set of LEDs in series. The power converter 102 is operative to convert the input DC voltage Vin to a desired DC output voltage Vout to power the LED chain 106. The switch 104 coupled to the power converter 102 can enable or disable the input voltage Vin to the LED chain 106 to turn the LED light on or off. Power converter 102 receives the feedback signal from current sense resistor Rsen and regulates output voltage Vout to cause LED chain 106 to produce the desired brightness. One of the disadvantages of this conventional solution is that the desired brightness is preset. In operation, the brightness output of the LED chain 106 is set to a predetermined value that the user cannot adjust.

FIG. 2 shows a schematic diagram of another conventional LED driving circuit 200. Power converter 102 converts the input DC voltage Vin to a desired DC output voltage Vout to power LED chain 106. The switch 104 coupled to the power converter 102 can enable or disable the input voltage Vin to the LED chain 106 to turn the LED light on or off. The LED chain 106 is coupled to a linear LED current regulator 208. The operational amplifier 210 in the linear LED current regulator 208 compares the reference signal REF with the current monitoring signal from the current detecting resistor Rsen and generates a control signal to adjust the impedance of the transistor Q1 in a linear mode. Therefore, the current flowing through the LED chain 106 can be adjusted accordingly. In this solution, in order to control the brightness output of the LED chain 106, the user needs to adjust the reference signal REF by using a dedicated device such as a specially designed switch having an adjustment button or receiving a remote control signal.

An object of the present invention is to provide a light source driving circuit comprising: a converter coupled to a power source, receiving power from the power source and providing a regulated power source to a light source according to the plurality of control signals; and a dimming controller And coupled to the converter, monitoring a power switch connected between the power source and the converter, the dimming controller receiving a color change signal indicating a first group of actions of the power switch, and receiving the indication a dimming request signal of a second group of actions of the power switch; wherein, when receiving the color change signal, the dimming controller controls the plurality of control signals to change a color of the light source, and the dimming controller is Receiving the dimming request signal, controlling the plurality of control signals to adjust a brightness of the light source.

The invention also provides a dimming controller for controlling electrical energy transmitted from a converter to a light source, comprising: a monitoring end point, receiving a monitoring signal indicating a connection between a power source and the converter a conductive state of the power switch; and a plurality of dimming terminals, the plurality of control signals are provided to control the electrical energy, wherein a color and a brightness of the light source are determined by the plurality of control signals, wherein the dimming controller Determining, based on the monitoring signal, a color change signal indicating a first set of actions of the power switch and a dimming request signal indicating a second set of actions of the power switch; when receiving the color change signal, the adjusting The light controller adjusts the plurality of control signals to change the color; when receiving the dimming request signal, the dimming controller adjusts the plurality of control signals to adjust the brightness.

The invention also provides a light source driving method, comprising: transmitting an electric energy from a converter to a light source; monitoring a power switch coupled between a power source and the converter; receiving a color change signal, the color change signal Determining a first set of actions of the power switch; adjusting a color of the light source according to the color change signal; receiving a dimming request signal, the dimming request signal indicating a second set of actions of the power switch; and according to the tune The light request signal adjusts a brightness of the light source.

A detailed description of the embodiments of the present invention will be given below. While the invention will be described in conjunction with the embodiments, it is understood that the invention is not limited to the embodiments. On the contrary, the invention is intended to cover various modifications, modifications and equivalents

In addition, in the following detailed description of the embodiments of the invention However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail in order to facilitate the invention.

3 is a block diagram of a light source driving circuit 300 in accordance with an embodiment of the present invention. In an embodiment, the light source driving circuit 300 includes an alternating current/direct current (AC/DC) converter 306 for converting an alternating current input voltage Vin from a power source into a direct current output voltage Vout, coupled to the power source and the alternating current/direct current converter. A power switch 304 for selectively coupling a power source to the light source driving circuit 300 between the 306, and a power converter 310 for providing regulated power to the LED chain 312 and the power converter with the AC/DC converter 306 The 310 is coupled to receive a switch monitoring signal indicative of operation of the power switch 304 and to adjust the regulated power from the power converter 310 based on the switch monitoring signal, and to monitor LED current flowing through the LED chain 312. Current sensor 314. In an embodiment, the power switch 304 is an on/off switch that is secured to the wall.

In operation, the AC/DC converter 306 converts the input AC voltage Vin into a DC output voltage Vout. Power converter 310 receives DC voltage Vout and provides regulated power to LED chain 312. Current sensor 314 generates a current sense signal that represents the LED current level flowing through LED chain 312. The dimming controller 308 monitors the operation of the power switch 304, receives the current sense signal from the current sensor 314, and controls the power converter 310 in response to operation of the power switch 304 to regulate the power of the LED chain 312. In one embodiment, dimming controller 308 operates in an analog dimming mode to adjust the power of LED chain 312 by adjusting a reference signal indicative of the peak current of the LED. In another embodiment, the dimming controller 308 operates in a burst dimming mode to adjust the power of the LED chain 312 by adjusting the duty cycle of a pulse width modulation (PWM) signal. By adjusting the power of the LED chain 312, the brightness output of the LED chain 312 can be adjusted accordingly.

4 is a circuit diagram of a light source driving circuit 400 in accordance with an embodiment of the present invention. Figure 4 will be described in conjunction with Figure 3. Elements in Figure 4 that are numbered the same as in Figure 3 have similar functions and will not be repeatedly described herein for the sake of brevity.

Light source drive circuit 400 includes a power converter 310 (shown in FIG. 3) coupled to power source and LED chain 312 for receiving power from a power source and providing regulated power to LED chain 312. In the example of FIG. 4, power converter 310 can be a buck converter that includes inductor L1, diode D4, and control switch Q16. In the embodiment shown in FIG. 4, control switch Q16 is located outside of dimming controller 308. In other embodiments, the control switch Q16 can be integrated into the dimming controller 308.

The dimming controller 308 receives a switch monitoring signal indicating an operation of a power switch (eg, a power switch 304 coupled between the power source and the light source driving circuit), and controls a control switch coupled in series with the LED chain 312 according to the switch monitoring signal. Q16 to regulate the regulated power from power converter 310 (including inductor L1, diode D4, and control switch Q16). The light source driving circuit 400 further includes an AC/DC converter 306 for converting the AC input voltage Vin into a DC output voltage Vout, and a current sensor 314 for monitoring the LED current flowing through the LED chain 312. In the example shown in FIG. 4, the AC/DC converter 306 can be a bridge rectifier including diodes D1, D2, D7, D8, D10 and capacitor C9. The current sensor 314 can include a current detecting resistor R5.

In an embodiment, the endpoints of dimming controller 308 include: HV_GATE, SEL, CLK, RT, VDD, CTRL, MON, and GND. The terminal HV_GATE is coupled to the switch Q27 via a resistor R3 for controlling the conduction state (eg, the on/off state) of the switch Q27 coupled to the LED chain 312. The capacitor C11 is coupled between the terminal HV_GATE and the ground for adjusting the gate voltage of the switch Q27.

The user may choose to select a dimming mode, such as analog dimming mode or sudden dimming mode, by connecting the terminal SEL to ground via resistor R4 (as shown in FIG. 4) or by directly connecting the terminal SEL to ground. .

Endpoint CLK is coupled to AC/DC converter 306 via resistor R3 and to ground via resistor R6. Endpoint CLK receives a switch monitoring signal representative of the operation of power switch 304. In one embodiment, the switch monitor signal is generated on a common node between resistor R3 and resistor R6. Capacitor C12 is coupled in parallel with resistor R6 for filtering unwanted noise. The terminal RT is coupled to ground via a resistor R7 for determining the frequency of the pulse signal generated by the dimming controller 308.

The terminal VDD is coupled to the switch Q27 via the diode D9 for powering the dimming controller 308. In one embodiment, an energy unit (such as capacitor C10) is coupled between terminal VDD and ground to power dimming controller 308 when power switch 304 is turned off. In another embodiment, the energy unit is integrated inside the dimming controller 308. The terminal GND is coupled to the ground.

The endpoint CTRL is coupled to the control switch Q16. Control switch Q16 is coupled in series with LED chain 312 and switch Q27 and coupled to ground via current sense resistor R5. The dimming controller 308 controls the conduction state (eg, the on and off states) of the control switch Q16 using a control signal via the endpoint CTRL to regulate the regulated power from the power converter 310. The terminal MON is coupled to the current sense resistor R5 for receiving a current sense signal indicative of the LED current flowing through the LED chain 312. When switch Q27 is turned on, dimming controller 308 regulates the LED current flowing through LED chain 312 by controlling control switch Q16.

In operation, when the power switch 304 is turned on, the AC/DC converter 306 converts the input AC voltage Vin into a DC output voltage Vout. The preset voltage on the terminal HV_GATE is applied to the switch Q27 via the resistor R3 to turn on the switch Q27.

If the dimming controller 308 turns on the control switch Q16, the DC voltage Vout will power the LED chain 312 and charge the inductor L1. The LED current flows through the inductor L1, the LED chain 312, the switch Q27, the control switch Q16, and the resistor R5 to ground. If the dimming controller 308 turns off the control switch Q16, the LED current flows through the inductor L1, the LED chain 312, and the diode D4. Inductor L1 is discharged to power LED chain 312. Accordingly, dimming controller 308 can regulate the regulated power from power converter 310 by controlling control switch Q16.

When power switch 304 is turned off, capacitor C10 is discharged to power dimming controller 308. The voltage across resistor R6 drops to zero, so a switch monitor signal indicating the power switch 304 shutdown operation can be monitored by dimming controller 308 via endpoint CLK. Similarly, when the power switch 304 is turned on, the voltage across the resistor R6 rises to a predetermined voltage value, so a switch monitor signal indicating that the power switch 304 is conducting can be monitored by the dimming controller 308 via the endpoint CLK. If a shutdown operation is detected, the dimming controller 308 can turn off the switch Q27 by pulling the voltage on the terminal HV_GATE to zero, thereby causing the LED chain 31 to be powered down after the inductor L1 has completed discharging. In response to the shutdown operation, dimming controller 308 adjusts a reference signal indicative of the desired brightness output of LED chain 312. Thus, when the power switch 304 is turned on next time, the LED chain 312 can produce a brightness output based on the adjusted desired brightness output. In other words, the brightness output of the LED chain 312 can be adjusted by the dimming controller 308 in response to the turn-off operation of the power switch 304.

FIG. 5 shows an illustrative architectural diagram of the dimming controller 308 of FIG. 4 in accordance with an embodiment of the present invention. Figure 5 will be described in conjunction with Figure 4. Elements in Figure 5 that are numbered the same as in Figure 4 have similar functions and will not be repeatedly described herein for the sake of brevity.

The dimming controller 308 includes a trigger monitoring unit 506, a dimmer 502, and a pulse signal generator 504. The trigger monitoring unit 506 is connected to ground via a Zener diode ZD1. The trigger monitoring unit 506 receives a switch monitoring signal indicating the operation of the external power switch 304 via the endpoint CLK, and generates a drive signal to drive the counter 526 when the operation of the external power switch 304 is detected at the endpoint CLK. The trigger monitoring unit 506 also further controls the conduction state of the switch Q27. The dimmer 502 generates a reference signal REF, adjusts the power of the LED chain 312 in an analog to dimming mode, or generates a control signal 538 that adjusts the duty cycle of the pulse width modulation signal PWM1 to regulate the power of the LED chain 312. The pulse signal generator 504 generates a pulse signal that can turn on the control switch Q16. The dimming controller 308 further includes a start and under voltage lockout (UVL) circuit 508 coupled to the terminal VDD for selectively turning on one or more of the dimming controllers 308 according to different power conditions. Components.

In an embodiment, the startup and undervoltage lockout circuit 508 will turn on all of the components in the dimming controller 308 when the voltage at the terminal VDD is above the first predetermined voltage. When the power switch 304 is turned off, if the voltage at the terminal VDD is lower than the second predetermined voltage, the startup and undervoltage lockout circuit 508 will turn off the dimming controller 308 other than the trigger monitoring unit 506 and the dimmer 502. Components to save energy. The startup and undervoltage lockout circuit 508 will further turn off the trigger monitoring unit 506 and the dimmer 502 when the voltage at the terminal VDD is below the third predetermined voltage. In an embodiment, the first preset voltage is higher than the second preset voltage, and the second preset voltage is higher than the third preset voltage. Because the dimming controller 308 can be powered by the capacitor C10 via the terminal VDD, the trigger monitoring unit 506 and the dimmer 502 can operate for a period of time even after the power switch 304 is turned off.

In dimming controller 308, terminal SEL is coupled to current source 532. The user can select the dimming mode by configuring the endpoint SEL (eg, coupling the endpoint SEL directly to ground or coupling the endpoint SEL to ground via a resistor). In an embodiment, the dimming mode is determined by measuring the voltage on the terminal SEL. If the terminal SEL is directly coupled to ground, the voltage on the terminal SEL is approximately zero. A control circuit (not shown) can turn on the switch 540 and turn off the switches 541 and 542. Thus, dimming controller 308 can operate in analog dimming mode and adjust the power of LED chain 312 by adjusting reference signal REF. In one embodiment, if the terminal SEL is coupled to ground via a resistor R4 having a predetermined resistance (as shown in FIG. 4), the voltage at the terminal SEL is greater than zero. The control circuit sequentially turns off the switch 540, the conduction switch 541, and the conduction switch 542. Therefore, the dimming controller 308 operates in the sudden dimming mode and adjusts the power of the LED chain 312 by adjusting the duty cycle of the pulse width modulation signal PWM1. In other words, different dimming modes can be selected via the conduction states of the control switches 540, 541, 542. The conduction state of the switches 540, 541, 542 is determined by the voltage at the terminal SEL.

Pulse signal generator 504 is coupled to ground via terminal RT and resistor R7 to generate pulse signal 536 for turning on switch Q16. The pulse signal generator 504 can have a different configuration and is not limited to the configuration shown in FIG.

In the pulse signal generator 504, the non-inverting input of the operational amplifier 510 receives the preset voltage V1. Therefore, the inverting input voltage of the operational amplifier 510 is also V1. Current I _RT flows to ground through terminal RT and resistor R7. The current I ₁ flowing through the metal oxide semiconductor field effect transistor (MOSFET) 514 and the MOSFET 515 is equal to the current I _RT . Since MOSFET 514 and MOSFET 512 form a current mirror, current I ₂ flowing through MOSFET 512 is also equal to current I _RT . The output of comparator 516 and the output of comparator 518 are coupled to the S input and R input of SR flip flop 520, respectively. The inverting input of comparator 516 receives a preset voltage V2. The non-inverting input of comparator 518 receives a preset voltage V3. In an embodiment, V2 is greater than V3 and V3 is greater than zero. Capacitor C4 is coupled between MOSFET 512 and ground and has a common node coupled between one end and a non-inverting input of comparator 516 and an inverting input of comparator 518. The Q output of the SR flip-flop 520 is coupled to the S input of the switch Q15 and the SR flip-flop 522. Switch Q15 is connected in parallel with capacitor C4. The on state of switch Q15 (eg, on/off) is determined by the Q output of SR flip-flop 520.

The initial voltage across capacitor C4 is approximately zero, less than V3. Therefore, the R input of the SR flip-flop 520 receives the digital signal 1 output from the comparator 518. The Q output of SR flip-flop 520 is set to digital signal 0, which turns off switch Q15. When the switch Q15 is turned off, with the capacitor C4 is charged by the current I _2, the voltage across the capacitor C4 rises. When the voltage across the capacitor C4 is greater than V2, the S input of the SR flip-flop 520 receives the digital signal 1 output by the comparator 516. The Q output of the SR flip-flop 520 is set to a digital signal 1, which turns on the switch Q15. When the switch Q15 is turned on, as the capacitor C4 is discharged via the switch Q15, the voltage across the capacitor C4 is lowered. When the voltage across capacitor C4 drops below V3, comparator 518 outputs digital signal 1, and the Q output of SR flip-flop 520 is set to digital signal 0, which turns off switch Q15. And then the capacitor C4 is charged by the current I _2. As such, via the above process, pulse signal generator 504 generates pulse signal 536 that includes a series of pulses at the Q output of SR flip-flop 520. Pulse signal 536 is passed to the S input of SR flip-flop 522.

The trigger monitoring unit 506 monitors the operation of the power switch 304 through the endpoint CLK, and when the operation of the power switch 304 is monitored at the endpoint CLK, a drive signal is generated to drive the counter 526. In one embodiment, when power switch 304 is turned "on", the voltage at terminal CLK rises to a level equal to the voltage across resistor R6 (shown in Figure 4). When power switch 304 is turned off, the voltage on terminal CLK drops to zero. Thus, a switch monitoring signal indicating the operation of power switch 304 can be monitored at endpoint CLK. In an embodiment, the trigger monitoring unit 506 generates a drive signal when a shutdown operation is detected at the endpoint CLK.

The trigger monitoring unit 506 also controls the conduction state of the switch Q27 through the terminal HV_GATE. When the power switch 304 is turned on, the breakdown voltage across the Zener diode ZD1 is applied to the switch Q27 via the resistor R3. Therefore, the switch Q27 is turned on. The trigger monitoring unit 506 can turn off the switch Q27 by pulling down the voltage of the terminal HV_GATE to zero. In an embodiment, when the shutdown operation of the power switch 304 is detected on the endpoint CLK, the trigger monitoring unit 506 turns off the switch Q27, and when the conduction operation of the power switch 304 is monitored on the endpoint CLK, the trigger monitoring unit 506 is triggered. Turn on the switch Q27.

In one embodiment, the dimmer 502 includes a counter 526 coupled to the trigger monitoring unit 506 for counting the operation of the power switch 304, and a digital/analog ratio (D/A) converter coupled to the counter 526. 528. The dimmer 502 also includes a pulse width modulation (PWM) signal generator 530 coupled to the digital/analog converter 528. Counter 526 is driven by a drive signal generated by trigger monitoring unit 506. Specifically, in one embodiment, when power switch 304 is turned off, trigger monitoring unit 506 monitors a negative edge on endpoint CLK and generates a drive signal. The count value of counter 526 should be incremented (e.g., incremented by one). The digit/analog converter 528 reads the count value from the counter 526 and generates a dimming signal (e.g., control signal 538 or reference signal REF) based on the count value. The dimming signal can be used to adjust the target power value of power converter 310, thereby adjusting the brightness output of LED chain 312.

In the sudden dimming mode, switch 540 is turned off and switches 541 and 542 are turned on. The inverting input of comparator 534 receives a reference signal REF1, which is a DC signal having a predetermined substantially constant voltage. The voltage of REF1 determines the LED current peak and therefore also the maximum brightness output of LED chain 312. The dimming signal may be a control signal 538 applied to the pulse width modulation signal generator 530 to adjust the duty cycle of the pulse width modulation signal PWM1. By adjusting the duty cycle of PWM1, the brightness of LED chain 312 can be adjusted to be no greater than the maximum brightness determined by REF1. For example, if the duty cycle of PWM1 is 100%, then LED chain 312 has a maximum brightness output. If the duty cycle of PWM1 is less than 100%, the luminance output of LED chain 312 is lower than the maximum luminance output.

In the analog dimming mode, switch 540 is turned on and switches 541 and 542 are turned off. The dimming signal can be an analog reference signal REF having an adjustable voltage. The digital/analog converter 528 adjusts the voltage of REF based on the count value of the counter 526. The voltage of REF determines the peak value of the LED current and therefore the average value of the LED current. Therefore, by adjusting REF, the luminance output of the LED chain 312 can be adjusted.

In an embodiment, the digital/analog converter 528 lowers the voltage of REF in response to an increase in the count value. For example, if the count value is 0, the digit/analog converter 528 adjusts the voltage of REF to V4. If the count value increases to 1 when the trigger monitoring unit 506 detects the turn-off operation of the power switch 304 at the terminal CLK, the digital/analog converter 528 adjusts the voltage of REF to V5, and V5 is less than V4. In another embodiment, the digital/analog converter 528 increases the voltage of REF in response to an increase in the count value.

In an embodiment, the counter value is reset to zero when the counter 526 reaches its maximum count value. For example, if the counter 526 is a 2-bit counter, the count value will be incremented from 0 to 1, 2, 3, and then returned to 0 after the fourth shutdown operation is monitored. Accordingly, the luminance output of the LED chain 312 is sequentially adjusted from the first level to the second level, the third level, and the fourth level, and then returns to the first level.

The inverting input of comparator 534 can selectively receive reference signal REF and reference signal REF1. For example, in analog dimming mode, the inverting input of comparator 534 receives reference signal REF via switch 540, while in the dimming dimming mode, the inverting input of comparator 534 receives reference signal REF1 via switch 541. The non-inverting input of comparator 534 is coupled to resistor R5 via terminal MON to receive current sense signal SEN from current sense resistor R5. The voltage of current sense signal SEN may represent the LED current flowing through LED chain 312 when switches Q27 and Q16 are turned on.

The output of comparator 534 is coupled to the R input of SR flip-flop 522. The Q output of SR flip-flop 522 is coupled to AND gate 524. The pulse width modulation signal PWM1 generated by the pulse width modulation signal generator 530 is applied to the AND gate 524. Gate 524 outputs a control signal that is controlled via terminal CTRL control Q16.

If the analog dimming mode is selected, switch 540 is turned "on" and switches 541 and 542 are turned "off". Switch Q16 is controlled by SR flip-flop 522. In operation, when the power switch 304 is turned on, the breakdown voltage across the Zener diode ZD1 causes the switch Q27 to conduct. In response to the pulse signal 536 generated by the pulse signal generator 504, the SR flip-flop 522 generates a digital signal 1 at the Q output to turn on the control switch Q16. The LED current flows through the inductor L1, the LED chain 312, the switch Q27, the control switch Q16, and the current sense resistor R5 to ground. Since the inductor L1 prevents a sudden change in the LED current, the LED current gradually increases. Therefore, the voltage across the current sense resistor R5 (ie, the voltage of the current sense signal SEN) increases. When the voltage of SEN is greater than the voltage of reference signal REF, comparator 534 generates digital signal 1 to the R input of SR flip-flop 522 to cause SR flip-flop 522 to generate digital signal 0 and turn off control switch Q16. After the control switch Q16 is turned off, the inductor L1 is discharged to supply power to the LED chain 312. The LED current flowing through the inductor L1, the LED chain 312, and the diode D4 is gradually reduced. When the SR flip-flop 522 receives a pulse again at the S input, the control switch Q16 is turned on, and the LED current flows to the ground again via the current sense resistor R5. When the voltage of the current sensing signal SEN is greater than the voltage of the reference signal REF, the control switch Q16 is turned off by the SR flip-flop 522. As described above, the reference signal REF determines the peak value of the current flowing through the LED and also determines the luminance output of the LED chain 312. By adjusting REF, the brightness output of LED chain 312 is adjusted.

In the analog dimming mode, if power switch 304 is turned off, capacitor C10 (shown in Figure 4) is discharged to power dimming controller 308. When the trigger monitoring unit 506 detects the turn-off operation of the power switch 304 at the terminal CLK, the count value of the counter 526 is incremented by one. In response to the shutdown operation of the power switch 304, the trigger monitoring unit 506 turns off the switch Q27. In response to a change in the count value, the digital/analog converter 528 adjusts the voltage of the reference signal REF from the first level to the second level. Therefore, when the power switch 304 is turned on, the luminance output of the LED chain 312 can be adjusted according to the adjustment of the reference signal REF.

If the sudden dimming mode is selected, switch 540 is turned off and switches 541 and 524 are turned on. The inverting input of comparator 534 receives a reference signal REF1 having a predetermined voltage. The control switch Q16 is controlled by both the SR flip-flop 522 and the pulse width modulation signal PWM1 via the AND gate 524. The reference signal REF1 determines the peak current of the LED current and also determines the maximum luminance output of the LED chain 312. The duty cycle of the pulse width modulation signal PWM1 determines the on/off time of the control switch Q16. When the pulse width modulation signal PWM1 is logic 1, the conduction state of the control switch Q16 is determined by the Q output terminal of the SR flip-flop 522. When the pulse width modulation signal PWM1 is logic 0, the control switch Q16 is turned off. By adjusting the duty cycle of the pulse width modulation signal PWM1, the power of the LED chain 312 can be adjusted accordingly. Therefore, the combination of the reference signal REF1 and the pulse width modulation signal PWM1 determines the luminance output of the LED chain 312.

In the sudden dimming mode, when the power switch 304 is turned off, the shutdown operation is monitored at the endpoint CLK by the trigger monitoring unit 506. The trigger monitoring unit 506 turns off Q27 and generates a drive signal. In response to the drive signal, the count value of counter 526 is incremented (e.g., incremented by one). The digital/analog converter 528 generates a control signal 538 such that the duty cycle of the pulse width modulated signal PWM1 is adjusted from the first level to the second level. Therefore, when the power switch 304 is turned on next time, the luminance output of the LED chain 312 will be adjusted according to the target luminance output determined by the reference signal REF1 and the pulse width modulation signal PWM1.

6 is an exemplary signal waveform diagram in analog dimming mode, including LED current 602 flowing through LED chain 312, pulse signal 536, V522 indicating SR flip-flop 522 output, V524 indicating gate 524 output. And the on/off state of the switch Q16. Figure 6 will be described in conjunction with Figures 4 and 5.

In operation, pulse signal generator 504 generates pulse signal 536. In response to each of the pulse signals 536, the SR flip-flop 522 produces a digital signal 1 at the Q output. The digital signal 1 at the Q output of the SR flip-flop 522 causes the control switch Q16 to conduct. When the control switch Q16 is turned on, the inductor L1 current ramps up and the LED current 602 increases. When the LED current 602 reaches the peak value Imax, that is, the voltage of the current sense signal SEN is substantially equal to the voltage of the reference signal REF, the comparator 534 generates the R signal input of the digital signal 1 to the SR flip-flop 522, so that the SR flip-flop 522 produces a digital signal 0 at the Q output. When the Q output of the SR flip-flop 522 is a digital signal 0, the control switch Q16 is turned off. When control switch Q16 is turned off, inductor L1 discharges power to LED chain 312 and LED current 602 decreases. In the analog dimming mode, by adjusting the reference signal REF, the LED average current can be adjusted accordingly, so that the luminance output of the LED chain 312 is adjusted.

7 is an exemplary signal waveform diagram in a sudden dimming mode, including a current 602 flowing through the LED chain 312, a pulse signal 536, a V522 indicating the output of the SR flip-flop 522, and a V524 indicating the output of the gate 524. The on/off state of the switch Q16 and the pulse width modulation signal PWM1 are controlled. Figure 7 will be described in conjunction with Figures 4 and 5.

When PWM1 is the digital signal 1, the correlation between the LED current 602, the pulse signals 536, V522, V524 and the on/off state of the control switch Q16 is similar to that of FIG. When PWM1 is a digital signal 0, the output of AND gate 524 becomes digital signal 0. Therefore, switch Q16 is turned off and LED current 602 is decreased. If PWM1 maintains the state of digital signal 0 long enough, LED current 602 will decrease to zero. In this sudden dimming mode, by adjusting the duty cycle of PWM1, the average LED current can be adjusted accordingly, so that the luminance output of the LED chain 312 is also adjusted.

FIG. 8 is a block diagram showing the operation of a light source driving circuit according to an embodiment of the invention. Figure 8 will be described in conjunction with Figure 5.

In the example shown in FIG. 8, whenever the trigger monitoring unit 506 monitors the shutdown operation of the power switch 304, the count value of the counter 526 is incremented by one. Counter 526 is a 2-bit counter with a maximum count of three.

In the analog dimming mode, the digital/analog converter 528 reads the count value from the counter 526 and reduces the voltage of the reference signal REF in response to the increase in the count value. The voltage of the reference signal REF determines the peak value Imax of the LED current, which also determines the average LED current value. In the sudden dimming mode, the digital/analog converter 528 reads the count value from the counter 526 and reduces the duty cycle of the pulse width modulation signal PWM1 (e.g., 25% lower each time) in response to an increase in the count value. Counter 526 is reset after reaching the maximum count value (eg, 3).

9 is a flow chart of a method of adjusting power to a light source, in accordance with an embodiment of the present invention. Figure 9 will be described in conjunction with Figures 4 and 5.

In step 902, the regulated power provided by the power converter (eg, power converter 310) powers the light source (eg, LED chain 312). In step 904, a switch monitoring signal is received (eg, received by dimming controller 308). The switch monitoring signal indicates operation of a power switch (such as power switch 304) coupled between the power source and the power converter. In step 906, a dimming signal is generated based on the switch monitoring signal. In step 908, a switch (eg, control switch Q16) coupled in series with the light source is controlled in accordance with the dimming signal to adjust the regulated power from the power converter. In an embodiment, in the analog dimming mode, the regulated power from the power converter is adjusted by comparing the dimming signal with a feedback current sensing signal indicative of the magnitude of the source current of the source. In another embodiment, in the sudden dimming mode, the regulated power from the power converter is adjusted by controlling the duty cycle of a pulse width modulated signal with the dimming signal.

Accordingly, embodiments in accordance with the present invention provide a light source driving circuit that can adjust the power of a light source in accordance with a switch monitoring signal that operates a power switch, such as a power switch that is fixed to a wall. The power of the light source is provided by a power converter and is regulated by a dimming controller via a switch that is coupled in series with the light source. Advantageously, as previously described, the user can adjust the brightness output of the light source by operation of a conventional power switch, such as a shutdown operation. Therefore, there is no need to use an additional device (such as an external dimmer or a specially designed switch with a dimming button), thus reducing costs.

FIG. 10 is a circuit diagram of a light source driving circuit 1000 in accordance with an embodiment of the present invention. Figure 10 will be described in conjunction with Figure 3. Elements in Figure 10 that are numbered the same as Figures 3 and 4 have similar functions.

Light source drive circuit 1000 includes a power converter 310 coupled to a power source and LED chain 312 for receiving power from a power source and providing regulated power to LED chain 312. The dimming controller 1008 monitors the operation of the power switch 304 coupled between the power source and the light source drive circuit 1000 by monitoring the voltage on the terminal CLK. The dimming controller 1008 receives a dimming request signal indicating a first plurality of operations of the power switch 304 and a dimming termination signal indicating a second plurality of operations of the power switch 304. The dimming controller 1008 receives the dimming request signal and the dimming termination signal via the endpoint CLK. The dimming controller 1008 can also continuously adjust the regulated power from the power converter 310 if a dimming request signal is received, and stop adjusting the regulated power from the power converter 310 if a dimming termination signal is received. In other words, once the first plurality of operations of the power switch 304 are monitored, the dimming controller 1008 continuously adjusts the regulated power from the power converter 310 until the second plurality of operations of the power switch 304 are monitored. In an embodiment, dimming controller 1008 regulates the regulated power from power converter 310 by controlling control switch Q16 coupled in series with LED chain 312.

FIG. 11 is a diagram showing an exemplary architecture of the dimming controller 1008 of FIG. 10 in accordance with an embodiment of the present invention. Figure 11 will be described in conjunction with Figure 10. Elements in Figure 11 that are numbered the same as Figures 4, 5, and 10 have similar functions.

In the example of FIG. 11, the architecture of dimming controller 1008 is similar to the architecture of dimming controller 308 of FIG. The difference is in the dimmer 1102 and the trigger monitoring unit 1106. In FIG. 11, the trigger monitoring unit 1106 receives the dimming request signal and the dimming termination signal via the endpoint CLK and generates a signal EN to enable or disable the clock generator 1104. The trigger monitoring unit 1106 also controls the conduction state of the switch Q27 coupled to the LED chain 312.

In the analog dimming mode, the dimmer 1102 generates a reference signal REF to adjust the power of the LED chain 312, or in the dimming mode, the dimmer 1102 generates a control signal 538 to adjust the duty cycle of the pulse width modulation signal PWM1. To regulate the power of the LED chain 312. In the example of FIG. 11, the dimmer 1102 includes a clock generator 1104 coupled to the trigger monitoring unit 1106 for generating a clock signal, a counter 1126 driven by the clock signal, and a digital bit coupled to the counter 1126. / Analog (D/A) converter 528. The dimmer 1102 also further includes a pulse width modulation (PWM) signal generator 530 coupled to a digital/analog ratio (D/A) converter 528.

In operation, when power switch 304 is turned "on" or "off", trigger monitoring unit 1106 can monitor the positive or negative edge of the voltage at endpoint CLK, respectively. For example, when power switch 304 is turned off, capacitor C10 discharges power to dimming controller 1108. The voltage across resistor R6 drops to zero. Therefore, the trigger monitoring unit 1106 can detect a voltage negative edge on the terminal CLK. Similarly, when the power switch 304 is turned on, the voltage across the resistor R6 rises to a predetermined voltage. Therefore, the trigger monitoring unit 1106 can monitor a positive voltage edge on the terminal CLK. As previously discussed, by monitoring the voltage on the terminal CLK, the trigger monitoring unit 1106 can monitor the operation of the power switch 304, such as a turn-on or turn-off operation.

In an embodiment, when the first plurality of operations of the power switch 304 are monitored, the trigger monitoring unit 1106 receives the dimming request signal via the endpoint CLK. When the second plurality of operations of the power switch 304 are monitored, the trigger monitoring unit 1106 receives the dimming termination signal via the endpoint CLK. In an embodiment, the first plurality of operations of power switch 304 includes a first shutdown operation and a subsequent first conduction operation. In an embodiment, the second plurality of operations of power switch 304 includes a second shutdown operation and a subsequent second conduction operation.

If the trigger monitoring unit 1106 receives the dimming request signal, the dimming controller 1108 begins to continuously adjust the regulated power from the power converter 310. In the analog dimming mode, dimming controller 1108 adjusts the voltage of reference signal REF to regulate the regulated power from power converter 310. In the sudden dimming mode, the dimming controller 1108 adjusts the duty cycle of the pulse width modulation signal PWM1 to regulate the regulated power from the power converter 310.

If the trigger monitoring unit 1106 receives the dimming termination signal, the dimming controller 1108 stops adjusting the regulated power from the power converter 310.

Figure 12 is a block diagram showing the operation of a light source driving circuit including the dimming controller 1108 of Figure 11 in accordance with an embodiment of the present invention. FIG. 12 will be described in conjunction with FIG. 10 and FIG.

It is assumed that the power switch 304 is turned off at the initial moment. In operation, in one embodiment, when the power switch 304 is turned on by the user, the LED chain 312 is powered by the regulated power from the power converter 310 to produce an initial brightness output. In the analog dimming mode, the initial luminance output is determined by the initial voltage of the reference signal REF. In the sudden dimming mode, the initial luminance output is determined by the initial duty cycle (eg, 100%) of the pulse width modulation signal PWM1. In one embodiment, the reference signal REF and the pulse width modulation signal PWM1 are generated by a digital/analog ratio (D/A) converter 528 based on the count value of the counter 1126. Therefore, the initial voltage of REF and the initial duty cycle of PWM1 are determined by the initial count value of counter 1126 (eg, 0).

To adjust the brightness of the LED chain 312, the user can apply a first plurality of operations to the power switch 304. Once the first plurality of operations of the power switch 304 are detected, a dimming request signal is generated. In an embodiment, the first plurality of operations includes a first shutdown operation and a subsequent first conduction operation. As such, the trigger monitoring unit 1106 monitors and receives the dimming request signal including the voltage negative edge 1204 and the subsequent positive edge 1206 at the endpoint CLK. In response to the dimming request signal, the trigger monitoring unit 1106 generates an EN signal having a high level. Thus, the clock generator 1104 is enabled to generate a clock signal. A counter 1126 driven by the clock signal can change the count value in response to each clock pulse of the clock signal. In the example of Figure 12, the count value is incremented in response to the clock signal. In one embodiment, the counter value is reset to zero when the counter 1126 reaches its preset maximum count value. In another embodiment, the count value is incremented until the counter 1126 reaches the preset maximum count value, and then the count value is decreased until the counter 1126 reaches the preset minimum count value.

In the analog dimming mode, the digital/analog ratio (D/A) converter 528 reads the count value from the counter 1126 and decreases the voltage of the reference signal REF in response to an increase in the count value. In the sudden dimming mode, the digital/analog ratio (D/A) converter 528 reads the count value from the counter 1126 and reduces the duty cycle of the pulse width modulation signal PWM1 in response to the increase in the count value (eg, 10 reductions per time). %). Accordingly, since the adjusted power from the power converter 310 is determined by the voltage of the reference signal REF (in the analog dimming mode) or by the duty cycle of the pulse width modulation signal PWM1 (in the dimming mode) Therefore, the brightness of the LED chain 312 can be adjusted.

Once the desired brightness output is reached, the user terminates the brightness by applying a second plurality of operations to the power switch 304. Once the second plurality of operations are detected, a dimming termination signal is generated. In an embodiment, the second plurality of operations includes a second shutdown operation and a subsequent second conduction operation. As such, the trigger monitoring unit 1106 monitors the dimming termination signal including the voltage negative edge 1208 and the subsequent positive edge 1210 at the endpoint CLK. Upon detecting the dimming termination signal, the trigger monitoring unit 1106 generates an EN signal having a low level. Therefore, the clock generator 1104 is disabled so that the counter 1126 keeps its count value unchanged. Accordingly, in the analog dimming mode, the voltage of the reference signal REF will remain at the desired level. In the sudden dimming mode, the duty cycle of the pulse width modulation signal PWM1 will remain at the desired value. Therefore, the luminance output of LED chain 312 will remain at the desired luminance output.

13 is a flow chart 1300 of a method of adjusting power of a light source, in accordance with an embodiment of the present invention. FIG. 13 will be described in conjunction with FIG. 10 and FIG.

In step 1302, the light source (eg, LED chain 312) is powered with the regulated power from a power converter (such as power converter 310).

In step 1304, a dimming request signal is received (as received by dimming controller 1108). The dimming request signal indicates a first plurality of operations of a power switch (eg, power switch 304) coupled between the power source and the power converter. In an embodiment, the first plurality of operations of the power switch includes a first shutdown operation and a subsequent first conduction operation.

In step 1306, the regulated power from the power converter is continuously adjusted (as adjusted by dimming controller 1108). In an embodiment, the clock generator 1104 is enabled to drive the counter 1126. A dimming signal (such as control signal 538 or reference signal REF) is generated based on the count value of counter 1126. In the analog dimming mode, the regulated power from the power converter is adjusted by comparing the reference signal REF with a feedback current sense signal indicative of the source current flowing through the source. The voltage of REF is determined by the count value. In the sudden dimming mode, the duty cycle of the pulse width modulation signal PWM1 is varied by control signal 538 to regulate the regulated power from the power converter. The duty cycle of PWM1 is determined by the count value.

In step 1308, a dimming termination signal is received (as received by dimming controller 1108). The dimming termination signal indicates a second plurality of operations of a power switch (eg, power switch 304) coupled between the power source and the power converter. In an embodiment, the second plurality of operations of the power switch includes a second shutdown operation and a second conduction operation thereafter.

In step 1310, if a dimming termination signal is received, then adjusting the regulated power from the power converter is stopped. In one embodiment, the clock generator 1104 is disabled to cause the counter 1126 to maintain its count value unchanged. As a result, in the analog dimming mode, the voltage of the reference signal REF is maintained at a desired level. In the sudden dimming mode, the duty cycle of the pulse width modulation signal PWM1 will remain at the desired value. Therefore, the power supply will maintain the desired brightness output.

Figure 14A is a circuit diagram of a light source driving circuit 1400 in accordance with an embodiment of the present invention. Elements in Figure 14A numbered the same as Figures 3, 4 and 10 have similar functions. Figure 14A will be described in conjunction with Figure 4.

The light source driving circuit 1400 is connected to the power source V _IN (such as 110/120 VAC, 60 Hz) through the power switch 1404, and is coupled to the light source 1412. Figure 14B shows an illustration of the power switch 1404 of Figure 14A, in accordance with one embodiment of the present invention. In one embodiment, the power switch 1404 is an ON/OFF switch placed on the wall. The closing or opening of the power switch 1404 can be controlled by switching the button 1480 to the ON or OFF position (as switched by the user).

As shown in FIG. 14A, the light source driving circuit 1400 includes an AC/DC converter 306, a converter 1410, and a dimming controller 1408. The AC/DC converter 306 converts the AC input voltage V _IN into a DC output voltage V _OUT . A converter 1410 coupled to the AC/DC converter 306 receives the DC output voltage V _OUT to provide output power to the light source 1412. A dimming controller 1408 coupled to the AC/DC converter 306 and the converter 1410 monitors the power switch 1404 and adjusts the output power of the converter 1410 according to the action of the power switch 1404 to control the color of the light emitted by the light source 1412. brightness. In an embodiment, dimming controller 1408 includes a plurality of endpoints, such as endpoint HV, endpoint CLK, endpoint VDD, endpoint GND, endpoint CTRL1, endpoint MON1, endpoint CTRL2, and endpoint MON2.

In one embodiment, light source 1412 includes a plurality of LED light sources, such as light source LED1 and light source LED2. For convenience of explanation, the light source LED1 shown in FIG. 14A includes an LED chain, and the light source LED 2 includes an LED chain. Or each of the light source LED1 and the light source LED2 includes a plurality of LED chains. The light source LED1 is capable of emitting a first color of light (such as a warm color). The light source LED2 is capable of emitting a second color of light (such as a cool color). Therefore, by controlling the light source LED1 and the light source LED2, the light source 1412 can emit light of different colors.

In one embodiment, converter 1410 includes power converters 1414 and 1416 coupled to source LEDs 1 and 2, respectively. The power converter 1414 is a buck converter including an inductor L29, a diode D25, a capacitor C26, a resistor R23, and a switch Q21. The switch Q21 is connected in series with the light source LED1. A switch control signal 1450 (such as a pulse width modulated PWM signal) controls the closing or opening of switch Q21. Similarly, power converter 1416 can also be a buck converter including inductor L30, diode D28, capacitor C27, resistor R33, and switch Q31. A switch control signal 1452 (such as a pulse width modulated PWM signal) controls the closing or opening of the control switch Q31 in series with the source LED2. Power converters 1414 and 1416 may also have other configurations and are not limited to the example of FIG. 14A.

Similar to the operation of the power converter 310 (shown in FIG. 4), the power converter 1414 supplies the adjusted power to the light source LED1 according to the conduction state of the switch Q21. More specifically, in one embodiment, switch Q21 is closed or Q21 is alternately closed and opened (ie, "on" state) to cause current to flow through source LED1. The power converter 1414 can operate in a sudden dimming mode or an analog dimming mode to adjust the adjusted electrical energy. For example, in the sudden dimming mode, the duty cycle of the switch control signal 1450 is adjusted to regulate the power supplied to the light source LED1. In the analog dimming mode, the current peak of the light source LED1 is adjusted according to the switch control signal 1450 to adjust the electric energy supplied to the light source LED1.

In addition, if switch Q21 is open and the duration of the off state exceeds a time threshold (ie, "off" state), the current through source LED1 drops to zero amps, thus turning off source LED1. The operation of power converter 1416 is similar to power converter 1414.

Based on the switch control signals 1450 and 1452, the converter 1410 selectively provides the adjusted electrical energy to the light sources LED1 and LED2. In one embodiment, one of the switches Q21 and Q31 is in an on state, powering the corresponding light source LED1 or LED2, and the other switch in the off state turns off the corresponding light source LED1 or LED2. For example, when power is supplied to LED 1 (eg, a warm white LED chain) and LED 2 is turned off (eg, a cool white LED chain), light source 1412 emits light having a warm color temperature. Similarly, when LED 1 is turned off and power is supplied to LED 2, light source 1412 emits light of a cool color temperature.

Thus, by adjusting the power supplied to light source 1412 (e.g., by adjusting switch control signals 1450 and 1452), the color and brightness of light source 1412 are controlled.

The dimming controller 1408 monitors the action of the power switch 1404 and accordingly generates corresponding switch control signals 1450 and 1452. When the power switch 1404 is turned on, the terminal HV coupled to the AC/DC converter 306 receives power from the power source V _IN and supplies power to the dimming controller 1408. In one embodiment, when the power switch 1404 is turned off, an electrical energy storage unit (eg, capacitor C24) coupled to the terminal VDD can power the dimming controller 1408. The terminal GND is coupled to the ground.

In one embodiment, the terminal MON1 is coupled to the resistor R23 to monitor the current through the light source LED1. Similarly, the terminal MON2 is coupled to the resistor R33 to monitor the current through the light source LED2.

In the example shown in FIG. 14A, dimming controller 1408 monitors power switch 1404 by monitoring the voltage of terminal CLK coupled to AC/DC converter 306. Through the endpoint CLK, the dimming controller 1408 receives a color change signal indicating a first set of actions of the power switch 1404, receives a dimming request signal indicating a second set of actions of the power switch 1404, and receives a third set of actions indicating the power switch 1404 The dimming termination signal. Based on the signals received by the endpoint CLK, the dimming controller 1408 generates switch control signals 1450 and 1452 to control the switches Q21 and Q31, respectively.

If a color change signal is received, the dimming controller 1408 changes the on state of the switches Q21 and Q31, thus changing the color of the light source 1412. For example, when the light of the light source 1412 has a warm color temperature (such as Q21 is in the on state and Q31 is in the off state), the dimming controller 1408 switches the switches Q21 and Q31 to the states of turning off and on, respectively. Therefore, the light color is switched to a cool color temperature. Similarly, if the light of the light source 1412 has a cool color temperature (eg, Q21 is in the off state and Q31 is in the on state), the dimming controller 1408 switches the switches Q21 and Q31 to the on and off, respectively. The state of the light. Therefore, the light color is switched to a warm color temperature.

If a dimming request signal is received, the dimming controller 1408 adjusts the brightness of the light source 1412 accordingly. For example, when the light of the light source 1412 has a warm color temperature (eg, Q21 is in the on state and Q31 is in the off state), the dimming controller 1408 controls the switch Q21 to operate in the sudden dimming mode or the analog dimming mode. The power supplied to the light source 1412 is increased or decreased for a predetermined period of time (e.g., _TTH2 ) or until a dimming termination signal is received. Similarly, when the light of the light source 1412 has a cool color temperature (such as Q21 is turned off and Q31 is turned on), the dimming controller 1408 controls the switch Q31 to operate in the sudden dimming mode or the analog dimming mode. Further, the power supplied to the power source 1412 is increased or decreased within a preset period of time (e.g., T _TH2 ) or until a dimming termination signal is received.

Advantageously, the user can control the color of the illumination by applying a first set of actions to the power switch 1404. The user can also control the brightness of the illumination by applying a second set of actions to the power switch 1404 such that the brightness of the light source 1412 gradually decreases or increases. If the desired brightness is reached, the user can terminate the brightness adjustment by applying a third set of actions to the power switch 1404. This eliminates the need for additional equipment for light color selection and dimming (such as an external remote controller or a specially designed switch with dimming buttons) for brightness adjustment, which in turn saves costs.

Figure 15 is a block diagram showing the configuration of the dimming controller 1408 of Figure 14A, in accordance with one embodiment of the present invention. Figure 15 will be described in conjunction with Figures 5 and 14A. Elements in Figure 15 that are numbered the same as Figures 5, 11, and 14A have similar functions.

In the example shown in FIG. 15, dimming controller 1408 includes a startup circuit 1502, a low voltage lockout circuit 1504, a trigger monitoring unit 1506, dimmers 1552 and 1554, a pulse signal generator 504, and logic circuits 1556 and 1558. When the power switch 1404 is turned "on", the enable circuit 1502 receives power from the terminal HV to provide a supply voltage for the terminal VDD. A low voltage lockout circuit 1504 coupled to the terminal VDD senses the supply voltage and controls the dimming controller 1408 based on the supply voltage. In one embodiment, low voltage lockout circuit 1504 turns on dimming controller 1408 when power switch 1404 is closed. When the power switch 1404 remains off and the duration is less than the time threshold _{TTH_VDD} , the capacitor C24 (shown in Figure 14A) discharges to provide power to the terminal VDD. Therefore, in this case, the dimming controller 1408 can still be powered and operate. However, if the power switch 1404 remains off and lasts longer than the time threshold T _{TH —} VDD , that is, the voltage at the terminal VDD drops to a preset threshold voltage V _THL . At this time, the low voltage lock circuit 1504 turns off the dimming controller 1408.

As described above with respect to FIG. 14A, the color change signal indicates a first set of actions of the power switch 1404, the dimming request signal indicates a second set of actions of the power switch 1404, and the dimming termination signal indicates a third set of actions of the power switch 1404. . In one embodiment, the first set of actions includes a first break action and a subsequent first close action, the second set of actions including a second break action and a subsequent second close action. In one embodiment, the first time interval between the first opening action and the first closing action is different than the second time interval between the second opening action and the second closing action. For example, the first time interval is greater than the time threshold T _TH1 (eg, 2 seconds) and the second time interval is less than T _TH1 .

Additionally, the third set of actions includes a third break action and a subsequent third close action. In one embodiment, the third opening action follows the second closing action, and the time interval between the second closing action and the third opening action is less than the second time threshold T _TH2 (eg, 10 seconds).

The trigger monitoring circuit 1506 coupled to the terminal CLK receives a monitoring signal indicating the conduction state of the power switch 1404 through the terminal CLK. Based on the monitoring signal, the trigger monitoring unit 1506 determines whether the power switch 1404 performs a closed action or a disconnected action. Through the timer 1508, the trigger monitoring circuit 1506 measures the time interval between different operations of the power switch 1404 (such as the time interval between a closing action and an opening action or the time interval between a closing action and another closing action). ). As a result, the trigger monitoring unit 1506 recognizes the color change signal, the dimming request signal, and the dimming termination signal.

The dimmer 1552 includes a counter 1510, a digital/analog converter 1512, a pulse width modulation signal generator 1514, and a clock generator 1516. Similar to the operation in the dimmer 1102 of FIG. 11, the dimmer 1552 generates a dimming signal PWM3 based on the count value stored by the counter 1510. In one embodiment, the duty cycle of the dimming signal PWM3 is determined by the count value. Logic circuit 1556 coupled to dimmer 1552 includes a comparator 1530, an SR flip-flop 1532, and a gate 1534. Similar to the operation of the circuit including comparator 534, SR flip-flop 522, and AND gate 524 (shown in FIG. 5), logic circuit 1556 generates switch control signal 1450 at terminal CTRL1 based on dimming signal PWM3. In one embodiment, the duty cycle of the switch control signal 1450 is determined by the count value of the counter 1510. Therefore, by controlling the switch Q21 according to the switch control signal 1450, it is possible to adjust the electric energy supplied to the light source LED1.

Similarly, dimmer 1554 includes a counter 1520, a digital/analog converter 1522, a pulse width modulation generator 1524, and a clock generator 1526. A dimmer 1554 is used to generate the dimming signal PWM4. Logic circuit 1558 coupled to dimmer 1554 includes a comparator 1540, an SR flip-flop 1542, and a gate 1544. Logic circuit 1558 generates a switch control signal 1452. The duty cycle of the dimming signal PWM4 and the switch control signal 1452 is determined by the count value of the counter 1520. Therefore, by controlling the switch Q31 according to the switch control signal 1452, it is possible to adjust the electric energy supplied to the light source LED2.

Table 1 depicts the count value of the counter 1510 or 1520 in accordance with one embodiment of the present invention, as well as the duty cycle of the switch control signal 1450 or 1452 corresponding to the count value. As shown in Table 1, if the count value is set to 0, the duty cycle is 0. Therefore, the corresponding control switch Q21 or Q31 operates in the off state to turn off the corresponding LED light source. If the count value is greater than 0 (such as 1 to 10), the duty cycle is greater than 0, so the corresponding switch Q21 or Q31 operates in the light-on state to supply power to the corresponding LED light source.

The low voltage lockout circuit 1504 detects the supply voltage at the terminal VDD. In one embodiment, low voltage lockout circuit 1504 adjusts the count values of counters 1510 and 1520 based on the supply voltage of terminal VDD. More specifically, when the supply voltage on the terminal VDD _falls below the threshold voltage _VTHL , the low voltage lockout circuit 1504 sets the count values of the counters 1510 and 1520 to the first set of preset values. When the power supply voltage of the terminal VDD rises above V _THL , the low voltage lock circuit 1504 sets the count values of the counters 1510 and 1520 to the second set of preset values. For example, when the power supply voltage drops below the threshold voltage V _THL , the count values of the counters 1510 and 1520 are both set to zero. Therefore, the light sources LED1 and LED2 are turned off. When the power supply voltage rises above V _THL , the count values of the counters 1510 and 1520 are set to 10 and 0, respectively. Therefore, the light source LED1 is turned on and the light source LED2 is turned off.

In one embodiment, dimming controller 1408 also includes a busbar 1560 for connecting dimmer 1552, dimmer 1554, and trigger monitoring unit 1506. In one embodiment, the trigger monitoring unit 1506 generates enable signals EN _COL , EN _{DIH1 ,} and EN _DIM2 for adjusting the count values of the counters 1510 and 1520.

More specifically, in one embodiment, when a color change signal is received, the trigger monitoring unit 1506 generates an enable signal EN _COL . Bus 1560 transmits enable signal EN _COL to counters 1510 and 1520. In one embodiment, the count values of counters 1510 and 1520 are interchanged to respond to enable signal EN _COL . For example, if the count values of the counters 1510 and 1520 are 5 and 0, respectively, it means that the light emitted by the light source 1412 has a warm color temperature (LED1 is on and LED2 is off). After receiving the enable signal EN _COL , the count values of the counters 1510 and 1520 become 0 and 5, respectively, so that the light source becomes a cool color temperature (LED1 is turned off and LED2 is turned on). The advantage is that although the color of the light is changed, the brightness of the light remains unchanged. Alternatively, the count values of the counters 1510 and 1520 can be changed to other values. For example, the count values of the counters 1510 and 1520 can be set to 0 and 10. In such a case, the color and brightness of the light change.

In one embodiment, if a dimming request signal is received, the trigger monitoring unit 1506 determines which switch is turned on by monitoring the count value, and accordingly generates a valid enable signal EN _DIMI to control the light-on state. switch. For example, if the switch Q21 is in the on state, the clock generator 1516 provides a clock signal _CLOCK1 to the counter 1510 based on the active enable signal EN _DIMI . Therefore, the counter 1510 adjusts the count value to adjust the brightness of the light source LED1. For example, the count value continuously increases, and thus the brightness of the light source LED1 gradually increases. If a dimming termination signal is received, or the brightness adjustment exceeds a predetermined time interval, the trigger monitoring unit 1506 generates an invalid enable signal EN _DIMI . Therefore, the clock signal CLOCK1 is terminated, and the counter 1510 stops adjusting the count value. That is, the brightness adjustment ends.

Therefore, by adjusting the count values of the counters 1510 and 1520, the electric energy supplied to the light source 1412 is adjusted, thereby realizing the change of the light color and the adjustment of the brightness.

Figure 16 is a timing chart showing the operation of a light source driving circuit including the dimming controller 1408 shown in Figure 15 in accordance with one embodiment of the present invention. Figure 16 will be described in conjunction with Figures 14A and 15. 16 depicts the voltage V _{CLK of} the terminal CLK, the enable signals EN _COL , EN _DIM1 and EN _DIM2 generated by the trigger monitoring unit 1506, the clock signals _CLOCK1 and _CLOCK2 , and the count values VALUE_1 510 and VALUE_1 520 of the counters 1510 and 1520. The example shown in Figure 16 describes how the brightness of the light source 1412 is adjusted.

At time t0, voltage V _CLK is low, indicating that power switch 1404 is off. In one embodiment, the count values VALUE_1 510 and VALUE_1 520 are both zero. Therefore, the switches Q21 and Q31 are both turned off, and the light sources LED1 and LED2 are turned off.

At time t1, the power switch 1404 is closed. The endpoint HV receives power from the AC/DC converter 306. At this point, the voltage at the terminal VDD rises to V _THL . In one embodiment, low voltage lockout circuit 1504 sets VALUE_1 510 and VALUE_1 520 to 10 and 0, respectively. Therefore, the switch Q21 is switched to the on state and the switch Q31 is kept off. Correspondingly, the light source 1412 emits light having a warm color temperature at time t1.

At time t2, voltage V _CLK has a negative edge indicating that power switch 1404 is off. At time t3, voltage V _CLK has a positive edge that indicates the closing action of power switch 1404. Since the time interval T1 between t2 and t3 is less than the first time threshold T _TH1 , the trigger monitoring unit 1506 recognizes that the dimming request signal is received. Therefore, at time t3, the trigger monitoring unit 1506 generates a valid enable signal EN _DIM1 such that the clock generator 1516 generates the clock signal CLOCK1. In the example shown in FIG. 16, the count value VALUE_1 510 is increased (eg, from 1 to 6), and the luminance of the light source 1412 is gradually increased.

At time t4, the negative edge of the voltage V _CLK is detected, indicating the opening action of the power switch 1404. At time t5, the positive edge of the voltage V _CLK is detected, indicating the closing action of the power switch 1404. Since the time interval T2 between t3 and t4 is less than the second time threshold T _TH2 , the trigger monitoring unit 1506 recognizes that the dimming termination signal is received. Correspondingly, the enable signal EN _DIM1 becomes inactive (eg, low) and the clock signal _{CLOCK1 is} terminated. Therefore, the count value VALUE_1 510 maintains the count value of 6 from the time t5, that is, the brightness of the light source 1412 is kept constant.

At time t6, voltage V _CLK has a negative edge indicating the disconnection of power switch 1404. The time interval during which the power switch is _turned off (such as the time interval from t6 to t7) reaches the time threshold T _{TH —} VDD , indicating that the power supply voltage at the terminal VDD drops to V _{TH — VDD} . Thus, in one embodiment, low voltage lockout circuit 1504 resets VALUE_1 510 and VALUE_1 512 to zero again. Therefore, at time t7, the light source 1412 is turned off.

Figure 17 is a diagram showing another operational timing diagram of a light source driving circuit including the dimming controller 1408 shown in Figure 15 in accordance with one embodiment of the present invention. Figure 17 will be described in conjunction with Figures 14A and 15. 17 depicts the voltage V _{CLK of} the terminal CLK, the enable signals EN _COL , EN _DIM1 and EN _DIM2 generated by the trigger monitoring unit 1506, the clock signals _CLOCK1 and _CLOCK2 , and the count values VALUE_1 510 and VALUE_1 520 of the counters 1510 and 1520. The example shown in Figure 17 describes how the color and brightness of the light source 1412 are adjusted.

At time t0', voltage V _CLK is low, indicating that power switch 1404 is off. The count values VALUE_1510 and VALUE_1520 are 0. Therefore, the switch Q21 and the switch Q31 are in the off state, and the LED 1 and the LED 2 are turned off.

At time t1', the power switch 1404 is turned "on". The low voltage lockout circuit 1504 sets VALUE_1 510 and VALUE_1 520 to 10 and 0, respectively. Therefore, the switch Q21 is switched to the on state and the switch Q31 is kept in the off state. Correspondingly, light source 1412 emits light having a warm color temperature.

At time t2', the voltage V _CLK has a negative edge. At time t3', the voltage V _CLK has a positive edge, that is, an off action occurs at time t2', and then a closing action occurs at time t3'. The time interval between t2' and t3' is greater than the first time threshold _TTH1 indicating that a color change signal is received. Thus, in one embodiment, the trigger monitoring unit 1506 generates a valid enable signal EN _COL (e.g., a pulse signal) at time t3' to exchange the count values stored in the counters 1510 and 1520. Therefore, VALUE_1510 and VALUE_1520 are set to 0 and 10, respectively. Correspondingly, the switch Q21 is switched to the off state, and the switch Q31 is switched to the on state. Therefore, at time t3', the color of the light source 1412 becomes a cool color temperature and its brightness remains unchanged.

At time t4', voltage V _CLK has a negative edge. At time t5', voltage V _CLK has a positive edge, i.e., an off action occurs at time t4', and then a closing action occurs at time t5'. The time interval between t4' and t5' is less than T _TH1 , indicating that the dimming request signal is received. In response, trigger monitoring unit 1506 generates a valid enable signal EN _DIM2 . Thereby, the clock signal CLOCK2 is generated, and the count value VALUE_1520 is increased (e.g., from 1 to 3), thereby gradually increasing the brightness of the light source 1412.

At time t6', the voltage V _CLK has a negative edge, and at time t7', the voltage V _CLK has a positive edge, that is, an off action occurs at time t6', and then a closing action occurs at time t7'. Due to the time t6 'to t7' is smaller than the interval between the T _TH2, it represents the dimming termination signal is received. In response, the enable signal EN _DIM2 becomes inactive and the clock signal CLOCK2 is terminated. Therefore, starting from time t7', the count value VALUE_1510 remains at 3 to keep the brightness of the light source 1412 unchanged.

At time t8 ', the voltage V _CLK has a negative edge, showing operation of the power switch 1404 is turned off. In one embodiment, the time interval during which the power switch 1404 is turned off (eg, from t8' to t9') reaches the time threshold _{TTH_VDD} , indicating that the supply voltage at the terminal VDD drops to _{VTH_VDD} . At this time, the low voltage lock circuit 1504 sets VALUE_1 510 and VALUE_1 520 to 0 again. Therefore, at time t9', the light source 1412 is turned off.

Figure 18 is a diagram showing still another operational timing diagram of a light source driving circuit including the dimming controller 1408 shown in Figure 15 in accordance with one embodiment of the present invention. Figure 18 will be described in conjunction with Figures 14A and 15. FIG. 18 depicts the voltage V _{CLK of} the terminal CLK, the enable signals EN _COL , EN _DIM1 and EN _DIM2 generated by the trigger monitoring unit 1506, the clock signals _CLOCK1 and _CLOCK2 , and the count values VALUE_1510 and VALUE_1520 of the counters 1510 and 1520. The example shown in Figure 18 describes how the brightness of the light source 1412 is adjusted.

The operation of the dimming controller 1408 is similar to the operation from t0 to t3 described in FIG. 16 during the time interval from t0" to t3". For example, the opening operation of the time t2" and the closing operation of the time t3" are recognized as the dimming request signal. Therefore, VALUE_1 510 is adjusted from time t3". At time t4", the brightness adjustment reaches a preset time interval T _TH2 . Therefore, the trigger monitoring unit 1506 generates a failed enable signal EN _DIM1 , and the clock signal CLOCK1 is terminated. VALUE_1510 remains at 10 from t4" and the brightness adjustment ends.

At time t5", the voltage V _CLK has a negative edge indicating that the power switch 1404 is turned off. At time t6", the time interval during which the power switch 1404 is turned off (eg, from t5" to t6") reaches the time threshold T _{TH_VDD} , indicating that the supply voltage of the terminal VDD drops to V _TH-VDD . In one embodiment, in response, low voltage lockout circuit 1504 again sets VALUE_1 510 and VALUE_1 520 to zero. Therefore, at time t6", the light source 1412 is turned off.

Returning to Figure 15, dimming controller 1408 can also operate in analog dimming mode to adjust the brightness of light source 1412. In one embodiment, the inverting input of comparator 1530 is coupled to the output of digital/analog converter 1512, and the inverting input of comparator 1540 is coupled to the output of digital/analog converter 1522. Therefore, the reference signals REF1 and REF2 are determined by the count values of the counters 1510 and 1520, respectively. Thereby, the peak value of the current transmitted through the light source LED1 and the LED 2 is controlled in accordance with the count value to realize the brightness adjustment.

19 is a flow chart 1900 of a method of powering a light source in accordance with one embodiment of the present invention. Figure 19 will be described in conjunction with Figures 14A-18. Although FIG. 19 discloses certain specific steps, these steps are merely examples. The present invention is suitable for performing other steps similar or equivalent to those of FIG.

In step 1902, electrical energy is transferred from converter 1410 to a light source (such as light source 1412).

In step 1904, a power switch (such as power switch 1404) coupled between the power source and converter 1410 is monitored.

In step 1906, a color change signal is received that indicates a first set of actions of a power switch, such as power switch 1404.

In step 1908, the color of the light source (e.g., light source 1412) is adjusted based on the color change signal.

In step 1910, a dimming request signal is received, the dimming request signal indicating a second set of actions of the power switch.

In step 1912, the brightness of the light source is adjusted based on the dimming request signal.

In one embodiment, a monitoring signal is received that indicates the conduction state of the power switch. According to the monitoring signal, various actions of the power switch are recognized, including an opening action and a closing action. The first set of actions and the second set of actions are identified based on the time interval between the actions. In one embodiment, the brightness is adjusted for a predetermined time interval (e.g., _TTH2 ), or until a dimming termination signal is received, the dimming termination signal indicating a third set of actions of the power switch 1404. In one embodiment, the color and brightness of the light source are adjusted by adjusting the count values of counters (e.g., counters 1522 and 1554).

As described above, the present invention discloses a light source driving circuit that drives an LED light source. The advantage is that the user can select the color of the light source by applying a first set of switching actions to the power switch, and can also adjust the brightness by applying a second set of switching actions to the power switch. During the brightness adjustment process, the brightness of the light source is gradually increased or decreased. When the LED light source reaches the desired brightness, the user terminates the brightness adjustment process by applying a third set of actions to the power switch. This saves costs by eliminating the need for additional components (such as an external remote controller or a specially designed switch with dimming buttons) for brightness adjustment.

The above detailed description and the accompanying drawings are only typical embodiments of the invention. It is apparent that various additions, modifications and substitutions are possible without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood by those skilled in the art that the present invention may be changed in form, structure, arrangement, ratio, material, element, element, and other aspects without departing from the scope of the invention. Therefore, the embodiments disclosed herein are intended to be illustrative and not restrictive, and the scope of the invention is defined by the appended claims

100. . . LED drive circuit

102. . . Power converter

104. . . switch

106. . . LED chain

200. . . LED drive circuit

208. . . Linear LED current regulator

210. . . Operational Amplifier

300. . . Light source driving circuit

304. . . Power switch

306. . . AC/DC converter

308. . . Dimming controller

310. . . Power converter

312. . . LED chain

314. . . Current monitor

400. . . Light source driving circuit

502. . . Light modulator

504. . . Pulse signal generator

506. . . Trigger monitoring unit

508. . . Startup and undervoltage lockout (UVL) circuits

510. . . Operational Amplifier

512, 514, 515. . . Metal oxide semiconductor field effect transistor (MOSFET)

516, 518. . . Comparators

520, 522. . . SR flip-flop

524. . . Gate

526. . . counter

528. . . Digital/analog converter

530. . . Pulse width modulation signal generator

532. . . Battery

534. . . Comparators

536. . . Pulse signal

538. . . control signal

540, 541, 542. . . switch

602. . . LED current

900. . . flow chart

902, 904, 906, 908. . . step

1000. . . Light source driving circuit

1008. . . Dimming controller

1102. . . Light modulator

1104. . . Clock generator

1106. . . Trigger monitoring unit

1126. . . counter

1204. . . Negative margin

1206. . . Positive edge

1208. . . Negative margin

1210. . . Positive edge

1300. . . flow chart

1302, 1304, 1306, 1308, 1310. . . step

1400. . . Light source driving circuit

1404. . . switch

1408. . . Dimming controller

1410. . . converter

1412. . . light source

1414, 1416. . . Power converter

1450, 1452. . . Switch control signal

1480. . . Button

1502. . . Startup circuit

1504. . . Low voltage lockout circuit

1506. . . Trigger monitoring unit

1508. . . Timer

1510. . . counter

1512. . . Digital/analog converter

1514. . . Pulse width modulation signal generator

1516. . . Clock generator

1520. . . counter

1522. . . Digital/analog converter

1524. . . Pulse width modulation signal generator

1526. . . Clock generator

1530. . . Comparators

1532. . . SR flip-flop

1534. . . Gate

1540. . . Comparators

1542. . . SR flip-flop

1544. . . Gate

1552, 1554. . . Light modulator

1556, 1558. . . Logic circuit

1560. . . Busbar

1900. . . flow chart

1902, 1904, 1906, 1908, 1910, 1912. . . step

The technical method of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments to make the features and advantages of the present invention more obvious. among them:

Figure 1 is a circuit diagram of a conventional LED driving circuit.

FIG. 2 is a circuit diagram of another conventional LED driving circuit.

3 is an exemplary block diagram of a light source driving circuit in accordance with an embodiment of the present invention.

4 is a schematic circuit diagram of a light source driving circuit in accordance with an embodiment of the present invention.

FIG. 5 is a block diagram showing an exemplary architecture of the dimming controller of FIG. 4 in accordance with an embodiment of the present invention.

6 is a diagram showing an exemplary signal waveform in analog dimming mode in accordance with an embodiment of the present invention.

FIG. 7 is a diagram showing an exemplary signal waveform in a sudden dimming mode according to an embodiment of the invention.

FIG. 8 is a block diagram showing the operation of a light source driving circuit including the dimming controller shown in FIG. 5 according to an embodiment of the invention.

9 is a flow chart of a method of adjusting power to a light source, in accordance with an embodiment of the present invention.

FIG. 10 is a diagram showing an exemplary circuit of a light source driving circuit according to an embodiment of the present invention.

11 is a diagram showing an exemplary architecture of the dimming controller of FIG. 10 in accordance with an embodiment of the present invention.

FIG. 12 is a block diagram showing the operation of a light source driving circuit including the dimming controller shown in FIG. 11 according to an embodiment of the invention.

13 is a flow chart of a method of adjusting power to a light source, in accordance with an embodiment of the present invention.

Figure 14A is a circuit diagram of a light source driving circuit in accordance with an embodiment of the present invention.

Figure 14B is a diagram of the power switch of Figure 14A, in accordance with one embodiment of the present invention.

Figure 15 is a block diagram showing the structure of the dimming controller of Figure 14A in accordance with one embodiment of the present invention.

Figure 16 is a timing chart showing the operation of a light source driving circuit in accordance with one embodiment of the present invention.

Figure 17 is a timing chart showing another operation of the light source driving circuit in accordance with one embodiment of the present invention.

Figure 18 is a diagram showing still another operational timing of the light source driving circuit in accordance with one embodiment of the present invention.

Figure 19 is a flow chart showing a method of adjusting power of a light source in accordance with one embodiment of the present invention.

306. . . AC/DC converter

1400. . . Light source driving circuit

1404. . . switch

1408. . . Dimming controller

1410. . . converter

1412. . . light source

1414, 1416. . . Power converter

1450, 1452. . . Switch control signal

Claims (16)

A light source driving circuit includes: a converter coupled to a power source, receiving power from the power source and providing a regulated light source for a light source according to the plurality of control signals; and a dimming controller coupled to the conversion And monitoring a power switch connected between the power source and the converter, the dimming controller receiving a color change signal indicating a first group of actions of the power switch, and receiving a second indicating the power switch a dimming request signal of the group action; wherein, when receiving the color change signal, the dimming controller controls the plurality of control signals to change a color of the light source, and the dimming controller receives the dimming When the signal is requested, the plurality of control signals are controlled to adjust a brightness of the light source; and wherein the dimming controller comprises: a trigger monitoring unit, receiving a monitoring signal indicating a conductive state of the power switch, and based on the monitoring The signal identifies the first set of actions and the second set of actions, the trigger monitoring unit further identifying a plurality of actions of the power switch based on the monitoring signal, and based on the plurality of For a time interval between the first group identifies the set of actions and the second action, which comprises a plurality of operation and a closing operation off operation. The light source driving circuit of claim 1, wherein the first group of actions comprises a first opening action and a subsequent first closing action, the second group of actions comprising a second breaking action and a second closing action, a time interval between the first opening action and the first closing action, and the second opening action and the second closing action The time interval between the work is different. The light source driving circuit of claim 1, wherein the dimming controller adjusts the brightness of the light source according to the dimming request signal until receiving a dimming termination indicating a third group of actions of the power switch signal. The light source driving circuit of claim 3, wherein the second group of actions comprises a first breaking action and a subsequent first closing action, the third group of actions comprising a second breaking action and Subsequent to a second closing action, a time interval between the first closing action and the second opening action is less than a time threshold. The light source driving circuit of claim 1, wherein the light source comprises a first light emitting diode light source having a first color and a second light emitting diode light source having a second color. The light source driving circuit of claim 1, wherein the dimming controller comprises: a plurality of dimmers, respectively adjusting a plurality of counter values of the plurality of counters according to the color change signal and the dimming request signal, The dimming controller separately adjusts the plurality of control signals according to the plurality of count values. The light source driving circuit of claim 6, wherein the dimming controller further comprises: a low voltage locking circuit coupled to the dimming controller to monitor a power supply voltage; wherein, when the power supply voltage drops to a low level The low voltage locking circuit sets the plurality of count values to a first set of preset values when a threshold voltage value is reached; and wherein, when the power supply voltage rises above the threshold voltage value The low voltage locking circuit sets the plurality of count values to a second set of preset values. The light source driving circuit of claim 6, wherein the dimming controller exchanges the plurality of counter values of the plurality of counters when the color change signal is received, the dimming controller according to the exchanged A plurality of count values adjust the plurality of control signals to change the color of the light source and maintain the brightness of the light source. A dimming controller for controlling power transmitted from a converter to a light source, comprising: a monitoring terminal, receiving a monitoring signal indicating a one of a power switch connected between a power source and the converter And a plurality of dimming terminals, wherein a plurality of control signals are provided to control the electrical energy, wherein a color and a brightness of the light source are determined by the plurality of control signals, wherein the dimming controller is based on the monitoring signal Identifying a color change signal indicating a first set of actions of the power switch and a dimming request signal indicating a second set of actions of the power switch; the dimming controller adjusting when receiving the color change signal The plurality of control signals to change the color of the light source; when receiving the dimming request signal, the dimming controller adjusts the plurality of control signals to adjust the brightness of the light source; and wherein the dimming The controller further includes: a trigger monitoring unit, based on the monitoring signal, identifying a plurality of actions including a closing action and a breaking action, measuring between the multiple actions And a time interval interval, and the color change signal and the dimming request signal are identified according to the time interval. The dimming controller of claim 9, wherein the plurality of control signals adjust the brightness of the light source according to the dimming request signal until a dimming termination signal is received. The dimming controller of claim 9, wherein the light source comprises: a first light emitting diode light source having a first color; and a second light emitting diode light source having a second color, wherein The plurality of control signals respectively control the first light emitting diode light source and the second light emitting diode. The dimming controller of claim 9, further comprising: a plurality of dimmers, respectively adjusting a plurality of counter values of the plurality of counters according to the color change signal and the dimming request signal, wherein the dimming control The plurality of control signals are adjusted based on the plurality of count values. The dimming controller of claim 12, further comprising: a power supply terminal, receiving a power supply voltage, wherein when the power supply voltage drops below a threshold voltage value, the dimming controller The plurality of count values are set to a first set of preset values; when the power supply voltage rises above the threshold voltage value, the dimming controller sets the plurality of count values to a second set of preset values. The dimming controller of claim 12, wherein the dimming controller exchanges the plurality of counter values of the plurality of counters when the color change signal is received, wherein the plurality of control signals are The exchanged plurality of count values change the color of the light source and maintain the The brightness of the light source. A light source driving method includes: transmitting a power from a converter to a light source; monitoring a power switch coupled between a power source and the converter; receiving a color change signal, the color change signal indicating the power switch a first group of actions; adjusting a color of the light source according to the color change signal; receiving a dimming request signal, the dimming request signal indicating a second group of actions of the power switch; adjusting the light according to the dimming request signal a brightness of the light source; receiving a monitoring signal indicating a conductive state of the power switch; identifying, according to the monitoring signal, a plurality of actions of the power switch, the plurality of actions including a disconnecting action and a closing action; A time interval between the plurality of actions identifies the first set of actions and the second set of actions. The light source driving method of claim 15, further comprising: adjusting the brightness of the light source when receiving the dimming request signal; and stopping adjusting the light source when receiving a dimming termination signal brightness.