US 12,207,368 B2
LED color and brightness control apparatus and method
Dongjie Cheng, Murphy, TX (US); Vijay Hugar, Hubballi (IN); Sumit Bhat, Hubballi (IN); and Joy Das, Shyamnagar (IN)
Assigned to Diodes Incorporated, Plano, TX (US)
Filed by Diodes Incorporated, Plano, TX (US)
Filed on May 17, 2022, as Appl. No. 17/663,707.
Prior Publication US 2023/0422373 A1, Dec. 28, 2023
Int. Cl. H05B 45/44 (2020.01); H05B 45/10 (2020.01); H05B 45/20 (2020.01); H05B 45/325 (2020.01); H05B 45/397 (2020.01)
CPC H05B 45/44 (2020.01) [H05B 45/10 (2020.01); H05B 45/20 (2020.01); H05B 45/325 (2020.01); H05B 45/397 (2020.01)] 22 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a bandgap voltage reference configured to generate a current reference for controlling a plurality of light emitting diode channels;
a plurality of MOSFET devices connected in parallel and coupled between a cathode of a light emitting diode channel and ground, wherein the plurality of MOSFET devices is configured to control a current flowing through the light emitting diode channel;
a control circuit configured to generate gate drive signals for the plurality of MOSFET devices, wherein the gate drive signals are configured to adjust the current flowing through the light emitting diode channel based on a predetermined color and a predetermined brightness level of the light emitting diode channel;
a current mirror having inputs coupled to the bandgap voltage reference through a first operation amplifier;
a set resistor coupled to the current mirror;
a current-to-voltage conversion device coupled to an output of the current mirror; and
a second operation amplifier coupled between the output of the current mirror and a gate of a transistor connected in series with the light emitting diode channel.