Multi-bleeder mode control for improved LED driver performance
First Claim
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1. A multi-bleeder circuit for a light-emitting diode (LED) driver circuit, the multi-bleeder circuit comprising:
- a first bleeder circuit;
a second bleeder circuit; and
a controller coupled to receive a line sense signal representative of an input voltage, a bleeder current sense signal representative of a current conducted through the second bleeder circuit, and a return current sense signal representative of a return current from a load, wherein the controller is further coupled to activate and deactivate the first and second bleeder circuits based on the line sense signal, the bleeder current sense signal, and the return current sense signal, wherein the input voltage comprises a phase-controlled rectified input voltage from a dimming circuit and a rectifier, and wherein the controller is configured to;
in response to the LED driver circuit turning on;
cause the first switching element to be in the OFF state; and
operate the second bleeder circuit in a first mode of operation;
in response to a supply voltage of the controller increasing to a supply threshold value;
cause the first switching element to be in the OFF state for a delay period after the supply voltage of the controller increases to the supply threshold value; and
operate the second bleeder circuit in a second mode of operation for the delay period after the supply voltage of the controller increases to the supply threshold value;
in response to determining that the dimming circuit has not performed phase-angle dimming after the delay period;
cause the first switching element to be in the OFF state; and
operate the second bleeder circuit in a fourth mode of operation;
in response to determining that the dimming circuit has performed leading-edge dimming after the delay period;
cause the first switching element to be in the ON state; and
operate the second bleeder circuit in the second mode of operation; and
in response to determining that the dimming circuit has performed trailing-edge dimming after the delay period;
cause the first switching element to be in the OFF state; and
operate the second bleeder circuit in a third mode of operation.
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Abstract
Various examples directed to phase-dimming LED driver input circuitry having multiple bleeder circuits activated by a controller with multi-bleeder mode control are disclosed. In one example, the input circuitry may include multiple bleeder circuits controlled by the controller in an open-loop or closed-loop configuration. The controller may selectively activate or deactivate the multiple bleeder circuits based on the input line voltage, the dimming state, and the type of dimming being implemented to improve performance of the LED driver by preventing or reducing shimmering/blinking and by reducing bleeder loss.
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Citations
23 Claims
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1. A multi-bleeder circuit for a light-emitting diode (LED) driver circuit, the multi-bleeder circuit comprising:
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a first bleeder circuit; a second bleeder circuit; and a controller coupled to receive a line sense signal representative of an input voltage, a bleeder current sense signal representative of a current conducted through the second bleeder circuit, and a return current sense signal representative of a return current from a load, wherein the controller is further coupled to activate and deactivate the first and second bleeder circuits based on the line sense signal, the bleeder current sense signal, and the return current sense signal, wherein the input voltage comprises a phase-controlled rectified input voltage from a dimming circuit and a rectifier, and wherein the controller is configured to; in response to the LED driver circuit turning on; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a first mode of operation; in response to a supply voltage of the controller increasing to a supply threshold value; cause the first switching element to be in the OFF state for a delay period after the supply voltage of the controller increases to the supply threshold value; and operate the second bleeder circuit in a second mode of operation for the delay period after the supply voltage of the controller increases to the supply threshold value; in response to determining that the dimming circuit has not performed phase-angle dimming after the delay period; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a fourth mode of operation; in response to determining that the dimming circuit has performed leading-edge dimming after the delay period; cause the first switching element to be in the ON state; and operate the second bleeder circuit in the second mode of operation; and in response to determining that the dimming circuit has performed trailing-edge dimming after the delay period; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a third mode of operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A light-emitting diode (LED) driver circuit comprising:
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an input to be coupled to receive an alternating current (ac) input voltage; a Triac dimming circuit coupled to the input to receive the ac input voltage and output a phase-controlled ac input voltage; a rectifier coupled to receive the phase-controlled ac input voltage and output a phase-controlled rectified input voltage; a power converter coupled to receive the phase-controlled rectified input voltage and output a regulated output signal to a load; a first bleeder circuit coupled between the rectifier and the power converter; a second bleeder circuit coupled between the rectifier and the power converter; and a controller coupled to receive a line sense signal representative of a voltage of the phase-controlled rectified input voltage, a bleeder current sense signal representative of a current conducted through the second bleeder circuit, and a return current sense signal representative of a return current from the load, wherein the controller is further coupled to activate and deactivate the first and second bleeder circuits based on the line sense signal, the bleeder current sense signal, and the return current sense signal, wherein the first bleeder circuit comprises a first switching element, and wherein the controller is coupled to activate and deactivate the first bleeder circuit by switching the first switching element between an ON state and an OFF state, wherein the second bleeder circuit comprises a second switching element, and wherein the controller is coupled to activate and deactivate the second bleeder circuit by switching the second switching element between and ON state and an OFF state, wherein the controller is configured to; in response to the LED driver circuit turning on; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a first mode of operation; in response to a supply voltage of the controller increasing to a supply threshold value; cause the first switching element to be in the OFF state for a delay period after the supply voltage of the controller increases to the supply threshold value; and operate the second bleeder circuit in a second mode of operation for the delay period after the supply voltage of the controller increases to the supply threshold value; in response to determining that the Triac dimming circuit has not applied phase-angle dimming to the ac input voltage after the delay period; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a fourth mode of operation; in response to determining that the Triac dimming circuit has applied leading-edge dimming to the ac input voltage after the delay period; cause the first switching element to be in the ON state; and operate the second bleeder circuit in the second mode of operation; and in response to determining that the Triac dimming circuit has applied trailing-edge dimming to the ac input voltage after the delay period; cause the first switching element to be in the OFF state; and operate the second bleeder circuit in a third mode of operation. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification