Light-emitting diode driving circuit and secondary side controller for controlling the same
First Claim
1. A light-emitting diode (LED) driving circuit, comprising:
- a conversion circuit, which converts an input voltage into an output voltage according to a control signal;
an LED module being coupled with the conversion circuit and emitting light according to the output voltage;
a current detector being coupled with the LED module and generating a current detection signal according to a current flowed through the LED module; and
a control module, including a secondary side control unit being coupled with the current detector and coupled with an isolation unit for receiving the signal output by the secondary side control unit and accordingly generating a secondary side signal, generating the control signal according to the current detection signal and a dimming signal, so as to control the output voltage at a first driving voltage or a second driving voltage;
wherein when the output voltage is controlled at the first driving voltage, the LED module is in a stably lighting state; and
when the output voltage is controlled at the second driving voltage, the LED module is close to a non-lighting state;
wherein the second driving voltage is approximate to a threshold voltage of the LED module.
1 Assignment
0 Petitions
Accused Products
Abstract
A light-emitting diode (LED) driving circuit and a secondary side controller for controlling the same control an output voltage of the LED driving circuit at a first driving voltage or a second driving voltage. When the output voltage is controlled at the first driving voltage, an LED module driven by the LED driving circuit is in a stably lighting state; and when the output voltage is controlled at the second driving voltage, the output voltage is approximately a threshold voltage of the LED module but higher than zero volt, so that the LED module is close to not emitting light. Therefore, in a dimming operation, the variation of voltage applied across the LED module is smaller than that in the conventional LED driving circuits to thereby protect the LED module against an excessive voltage stress and avoid the problem of inaccurate dimming.
121 Citations
17 Claims
-
1. A light-emitting diode (LED) driving circuit, comprising:
-
a conversion circuit, which converts an input voltage into an output voltage according to a control signal; an LED module being coupled with the conversion circuit and emitting light according to the output voltage; a current detector being coupled with the LED module and generating a current detection signal according to a current flowed through the LED module; and a control module, including a secondary side control unit being coupled with the current detector and coupled with an isolation unit for receiving the signal output by the secondary side control unit and accordingly generating a secondary side signal, generating the control signal according to the current detection signal and a dimming signal, so as to control the output voltage at a first driving voltage or a second driving voltage; wherein when the output voltage is controlled at the first driving voltage, the LED module is in a stably lighting state; and
when the output voltage is controlled at the second driving voltage, the LED module is close to a non-lighting state;wherein the second driving voltage is approximate to a threshold voltage of the LED module. - View Dependent Claims (2, 3, 4)
-
-
5. An LED driving circuit, comprising:
-
a conversion circuit, which converts an input voltage into an output voltage according to a control signal; an LED module being coupled with the conversion circuit and emitting light according to the output voltage; a current detector being coupled with the LED module and generating a current detection signal according to a current flowed through the LED module; a voltage detector being coupled with the LED module and generating a voltage detection signal according to a voltage applied across the LED module; and a control module, which generates the control signal according to the current detection signal, the voltage detection signal, and a dimming signal, so as to control the output voltage at a first driving voltage or a second driving voltage; wherein when the output voltage is controlled at the first driving voltage, the LED module is in a stably lighting state; and
when the output voltage is controlled at the second driving voltage, the LED module is close to a non-lighting state;wherein the second driving voltage is approximate to a threshold voltage of the LED module. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
Specification