Active bleeder circuit triggering TRIAC in all phase and light emitting device power supply circuit and TRIAC control method using the active bleeder circuit

1. A light emitting device power supply circuit, comprising:

a tri-electrode AC switch (TRIAC) dimmer circuit, for generating a phase-cut AC dimming signal, wherein the phase-cut AC dimming signal has an OFF phase and an ON phase;

a rectifier circuit, which is coupled to the TRIAC dimmer circuit, for generating a rectified dimming signal according to the phase-cut AC dimming signal, wherein the rectified dimming signal has an OFF phase and an ON phase corresponding to the OFF phase and the ON phase of the phase-cut AC dimming signal;

a light emitting device driver circuit, for driving a light emitting circuit according to the rectified dimming signal; and

an active bleeder circuit, including:

a detection circuit, which is coupled to the rectifier circuit, for generating a detection signal and accumulating the detection signal in the OFF phase; and

a current sinker circuit, which is coupled to the detection circuit, for generating a latching current to trigger the TRIAC dimmer circuit by operating a switch therein when the detection signal exceeds a predetermined level;

wherein the detection circuit includes:

a conversion device, for converting the rectified dimming signal to the detection signal;

a storage device, for storing and accumulating the detection signal; and

an OFF control circuit, for turning OFF the switch of the current sinker circuit in the ON phase,

wherein the OFF control circuit includes a Zener diode, which has a reverse end coupled to the detection signal, and a forward end coupled to a relatively lower level, such that when a voltage difference between the detection signal and the relatively lower level exceeds a reverse breakdown voltage of the Zener diode, the Zener diode turns ON reversely.

2. The light emitting device power supply circuit of claim 1 , wherein the current sinker circuit turns OFF the switch therein to stop generating the latching current in the ON phase.

3. A light emitting device power supply circuit, comprising:

a tri-electrode AC switch (TRIAC) dimmer circuit, for generating a phase-cut AC dimming signal wherein the phase-cut AC dimming signal has an OFF phase and an ON phase;

a rectifier circuit, which is coupled to the TRIAC dimmer circuit, for generating a rectified dimming signal according to the phase-cut AC dimming signal, wherein the rectified dimming signal has an OFF phase and an ON phase corresponding to the OFF phase and the ON phase of the phase-cut AC dimming signal;

light emitting device driver circuit, for driving a light emitting circuit according to the rectified dimming signal; and

an active bleeder circuit, including:

a detection circuit, which is coupled to the rectifier circuit, for generating a detection signal and accumulating the detection signal in the OFF phase; and

a current sinker circuit, which is coupled to the detection circuit, for generating a latching current to trigger the TRIAC dimmer circuit by operating a switch therein when the detection signal exceeds a predetermined level;

wherein the detection circuit includes;

a conversion device, for converting the rectified dimming signal to the detection signal;

a storage device, for storing and accumulating the detection signal; and

a reset circuit, for resetting the detection signal.

4. The light emitting device power supply circuit of claim 3 , wherein the reset circuit includes a diode, which has a forward end coupled to the storage device, and a reverse end for receiving a reset signal to reset the detection signal.

5. An active bleeder circuit, comprising:

a detection circuit, coupled to a rectified signal having an OFF phase and an ON phase, for generating a detection signal according to the rectified signal and accumulating the detection signal in the OFF phase of the rectified signal; and

a current sinker circuit, which is coupled to the detection circuit, for generating a latching current by operating a switch therein when the accumulated detection signal exceeds a predetermined level;

wherein the detection circuit includes:

a conversion device, for converting the rectified signal to the detection signal;

a storage device, for storing and accumulating the detection signal; and

an OFF control circuit, for turning OFF the switch of the current sinker circuit in the ON phase,

wherein the OFF control circuit includes a Zener diode, which has a reverse end coupled to the detection signal, and a forward end coupled to a relatively lower level, such that when a voltage difference between the detection signal and the relatively lower level exceeds a reverse breakdown voltage of the Zener diode, the Zener diode turns ON reversely.

6. The active bleeder circuit of claim 5 , wherein the current sinker circuit turns OFF the switch therein to stop generating the latching current in the ON phase.

7. An active bleeder circuit, comprising:

a detection circuit, coupled to a rectified signal having an OFF phase and an ON phase, for generating a detection signal according to the rectified signal and accumulating the detection signal in the OFF phase of the rectified signal; and

a current sinker circuit, which is coupled to the detection circuit, for generating latching current by operating a switch therein when the accumulated detection signal exceeds a predetermined level;

wherein the detection circuit includes:

a conversion device, for converting the rectified signal to the detection signal;

a storage device, for storing and accumulating the detection signal; and

a reset circuit, for resetting the detection signal.

8. The active bleeder circuit of claim 7 , wherein the reset circuit includes a diode, which has a forward end coupled to the storage device, and a reverse end for receiving a reset signal to reset the detection signal.

9. A TRIAC (tri-electrode AC switch) control method, comprising:

receiving a rectified signal having an OFF phase and an ON phase, wherein the rectified signal is generated by rectifying a phase-cut AC signal generated by a TRIAC circuit;

generating a detection signal according to the rectified signal and accumulating the detection signal in the OFF phase; and

when the accumulated detection signal exceeds a predetermined level, generating a latching current to trigger the TRIAC circuit;

wherein the step of generating and accumulating the detection signal further includes: resetting the detection signal periodically.

10. The TRIAC control method of claim 9 further comprising: stopping generating the latching current in the ON phase.

11. The TRIAC control method of claim 9 , wherein the step of generating and accumulating the detection signal includes: charging a capacitor by a current according to the rectified signal in the OFF phase.

12. The TRIAC control method of claim 11 further comprising: discharging the capacitor in the ON phase.