LED (light-emitting diode) string derived controller power supply
First Claim
1. A lighting circuit, comprising:
- a plurality of sets of series-connected light-emitting diodes (LEDs), wherein a first LED set of one or more of the LEDs includes a first terminal coupled between an input voltage source terminal and an auxiliary power supply terminal and a second LED set of one or more of the LEDs includes a current input terminal and a ground terminal;
a switching power converter having a magnetic energy-storing element and a switching element for controlling a current supplied through the plurality of series connected light-emitting diodes;
a control circuit for controlling the switching element of the switching power converter, wherein;
the control circuit includes a power supply input terminal coupled to the auxiliary power supply terminal of the first LED set;
a switching circuit, wherein the switching circuit includes;
a first switch coupled to the auxiliary power supply terminal of the first LED set and the ground terminal of the second LED set;
a second switch coupled between the auxiliary power supply terminal of the first LED set and the current input terminal of the second LED set;
a string controller circuit coupled to control terminals of the first and second switches, wherein the string controller circuit is configured to;
generate a first control signal to control the first switch to alternately allow current to flow from the auxiliary power supply terminal to the control circuit and shunt the auxiliary power supply terminal to the ground terminal; and
generate a second control signal to control the second switch to intermittently couple the auxiliary power supply terminal to the current input terminal of the second LED set.
4 Assignments
0 Petitions
Accused Products
Abstract
An LED lighting device includes an auxiliary power supply that supplies power to a control circuit of the LED lighting device that receives an input from a terminal of a light-emitting diode (LED) string of the lighting device that has a substantially lower voltage than the line voltage to which the lighting device is connected. The terminal may be within the LED string, or may be an end of the string. A linear regulator may be operated from the voltage drop across a number of the LEDs in the string so that the energy wasted by the auxiliary power supply is minimized. In other designs, the auxiliary power supply may be intermittently connected in series with the LED string only when needed. The intermittent connection can be used to forward bias a portion of the LED string when the voltage supplied to the LED string is low, increasing overall brightness.
-
Citations
18 Claims
-
1. A lighting circuit, comprising:
-
a plurality of sets of series-connected light-emitting diodes (LEDs), wherein a first LED set of one or more of the LEDs includes a first terminal coupled between an input voltage source terminal and an auxiliary power supply terminal and a second LED set of one or more of the LEDs includes a current input terminal and a ground terminal; a switching power converter having a magnetic energy-storing element and a switching element for controlling a current supplied through the plurality of series connected light-emitting diodes; a control circuit for controlling the switching element of the switching power converter, wherein; the control circuit includes a power supply input terminal coupled to the auxiliary power supply terminal of the first LED set; a switching circuit, wherein the switching circuit includes; a first switch coupled to the auxiliary power supply terminal of the first LED set and the ground terminal of the second LED set; a second switch coupled between the auxiliary power supply terminal of the first LED set and the current input terminal of the second LED set; a string controller circuit coupled to control terminals of the first and second switches, wherein the string controller circuit is configured to; generate a first control signal to control the first switch to alternately allow current to flow from the auxiliary power supply terminal to the control circuit and shunt the auxiliary power supply terminal to the ground terminal; and generate a second control signal to control the second switch to intermittently couple the auxiliary power supply terminal to the current input terminal of the second LED set. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method of generating an auxiliary power supply for a circuit controlling the transfer of power from an input voltage source to a lighting device comprising plurality of sets of series-connected light-emitting diodes (LEDs) the method comprising:
-
controlling a switching circuit to charge a magnetic energy-storing element from the input voltage source and discharging of the magnetic energy-storing element to apply energy stored in the magnetic energy-storing element to the sets of LEDs; generating an auxiliary power supply voltage supplied to a power supply input terminal of the control circuit from auxiliary power supply terminal of a first LED set of one or more LEDs of plurality of sets of LEDs; and controlling a first switch, coupled to the auxiliary power supply terminal of the first LED set and a ground terminal, with a first control signal to alternately couple the auxiliary power supply terminal to the control circuit and shunt the auxiliary power supply terminal to the ground terminal; and controlling a second switch, coupled between the auxiliary power supply terminal of the first LED set and a current input terminal of a second LED set of one or more LEDs of plurality of sets of LEDs, with a second control signal to alternately couple the auxiliary power supply terminal to the current input terminal of the second LED set. - View Dependent Claims (9, 10, 11, 12)
-
-
13. An integrated circuit for operating a lighting circuit comprising a switching power converter and a plurality of a plurality of sets of series-connected light-emitting diodes (LEDs) coupled between an input voltage source terminal and a ground terminal associated with the input voltage source, the integrated circuit comprising:
-
a control circuit for controlling a switching element of the switching power converter wherein; the control circuit includes a power supply input terminal coupled to an auxiliary power supply terminal of a first LED set of one or more LEDs of plurality of sets of LEDs; a switching circuit, wherein the switching circuit includes; a first switch coupled to the auxiliary power supply terminal of the first LED set and the ground terminal of a second LED set of one or more LEDs of plurality of sets of LEDs; a second switch coupled between the auxiliary power supply terminal of the first LED set and a current input terminal of the second LED set; a string controller circuit coupled to control terminals of the first and second switches, wherein the string controller circuit is configured to; generate a first control signal to control the first switch to alternately couple the auxiliary power supply terminal to the control circuit and shunt the auxiliary power supply terminal to the ground terminal; and generate a second control signal to control the second switch to alternately couple the auxiliary power supply terminal to the current input terminal of the second LED set. - View Dependent Claims (14, 15, 16, 17, 18)
-
Specification