PFC LED DRIVER HAVING A FLICKER CONTROL MECHANISM
First Claim
1. A PFC LED driver having a flicker control mechanism, comprising:
- a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power;
a single stage PFC constant average current converter, coupled with said bridge rectifier and used for forcing an input current to track said full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and
a current ripple reducing unit, in series with an LED module to form a load for said output current to flow through, wherein said current ripple reducing unit has a negative feedback control mechanism for forcing a peak of said output current approach an average value of said output current.
1 Assignment
0 Petitions
Accused Products
Abstract
A PFC LED driver having a flicker control mechanism, including: a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power; a single stage PFC constant average current converter, coupled with the bridge rectifier and used for forcing an input current to track the full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a current ripple reducing unit, in series with an LED module to form a load for the output current to flow through, wherein the current ripple reducing unit has a negative feedback control mechanism for forcing a peak of the output current approach an average value of the output current.
-
Citations
9 Claims
-
1. A PFC LED driver having a flicker control mechanism, comprising:
-
a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power; a single stage PFC constant average current converter, coupled with said bridge rectifier and used for forcing an input current to track said full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a current ripple reducing unit, in series with an LED module to form a load for said output current to flow through, wherein said current ripple reducing unit has a negative feedback control mechanism for forcing a peak of said output current approach an average value of said output current. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A PFC LED driver having a flicker control mechanism, comprising:
-
a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power; a single stage PFC constant average current converter, coupled with said bridge rectifier and used for forcing an input current to track said full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a current ripple reducing unit, in series with an LED module to form a load for said output current to flow through, said current ripple reducing unit including; an amplifier, having a positive input, a negative input, and an output; an NMOS transistor, having a gate, a drain, and a source, said gate being coupled with said output of said amplifier, said drain being coupled with said LED module, and said source being coupled with said positive input of said amplifier; a first resistor, having one end coupled with said source of said NMOS transistor, and another end coupled to a ground; a peak detector, having an input coupled with said source of said NMOS transistor, and an output for providing a first voltage corresponding to a peak value of said output current; a low-pass filter, having an input coupled with said source of said NMOS transistor, and an output for providing a second voltage corresponding to an average value of said output current; a comparator, having a positive input for receiving said first voltage, a negative input for receiving said second voltage, and an output for providing a comparison signal; and a variable peak current setting unit, having an input for receiving said comparison signal, and an output for providing a peak control voltage to said negative input of said amplifier, wherein said peak control voltage increases/decreases as a high level period of said comparison signal increases/decreases. - View Dependent Claims (7)
-
-
8. A PFC LED driver having a flicker control mechanism, comprising:
-
a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power; a single stage PFC constant average current converter, coupled with said bridge rectifier and used for forcing an input current to track said full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a current ripple reducing unit, in series with an LED module to form a load for said output current to flow through, said current ripple reducing unit including; a first amplifier, having a first positive input, a first negative input, and a first output; a first NMOS transistor, having a gate coupled with said first output of said first amplifier, a drain coupled with said LED module, and a source coupled with said first negative input of said first amplifier; a first resistor, having one end coupled with said source of said first NMOS transistor, and another end coupled to a ground; a peak detector, having an input coupled with said source of said first NMOS transistor, and an output for providing a first voltage corresponding to a peak value of said output current; a low-pass filter, having an input coupled with said source of said first NMOS transistor, and an output for providing a second voltage corresponding to an average value of said output current; a comparator, having a positive input for receiving said first voltage, a negative input for receiving said second voltage, and an output for providing a comparison signal; and a variable peak current setting unit, having an input for receiving said comparison signal, and an output for providing a peak control voltage to said first positive input of said first amplifier, wherein said peak control voltage decreases/increases as a high level period of said comparison signal increases/decreases. - View Dependent Claims (9)
-
Specification