US 10,542,597 B2
Lighting control circuit and method for multiple LEDs
Poh Ng, Winchester, MA (US)
Assigned to SIGNIFY HOLDING B.V., Eindhoven (NL)
Appl. No. 15/757,741
Filed by SIGNIFY HOLDING B.V., Eindhoven (NL)
PCT Filed Sep. 2, 2016, PCT No. PCT/EP2016/070733
§ 371(c)(1), (2) Date Mar. 6, 2018,
PCT Pub. No. WO2017/042101, PCT Pub. Date Mar. 16, 2017.
Claims priority of provisional application 62/217,543, filed on Sep. 11, 2015.
Prior Publication US 2018/0352622 A1, Dec. 6, 2018
Int. Cl. H05B 33/08 (2006.01)
CPC H05B 33/0827 (2013.01) [H05B 33/0866 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A lighting control circuit, comprising:
a controller configured to generate a first drive signal, a second drive signal, the second drive signal being temporally non-overlapping with respect to the first drive signal;
a reference control circuit configured to generate a reference voltage;
a current source configured to deliver a current to a first LED and a second LED, wherein the current is proportional to the reference voltage so that a desired value of the current is achieved when the reference voltage has a high value;
a first switch configured to switch from an open position, when driven by the first drive signal having a low value, to a closed position when driven by the first drive signal having a high value, wherein the first switch is positioned to interrupt current flow through the first LED when the first switch is in the open position; and
a second switch configured to switch from an open position, when driven by the second drive signal having a low value, to a closed position when driven by the second drive signal having a high value, wherein the second switch is positioned to interrupt current flow through the second LED when the second switch is in the open position,
wherein the reference control circuit is arranged to generate the high value of the reference voltage only after one of the first drive signal and the second drive signal has the high value, and
wherein the current from the current source is adjustable by a current control loop that is configured to receive the reference voltage as an input,
wherein the reference control circuit comprises:
a first voltage source having a first voltage value being configured to set the value of the reference voltage to the first voltage value when a first switch is in a closed position; and
a second voltage source having a second voltage value being configured to set the value of the reference voltage to the second voltage value when a second switch is in a closed position.