US 12,452,975 B2
LED driving circuit and method for controlling a current distribution to an LED string
Chia-Lung Ni, New Taipei (TW); Zheng Luo, San Jose, CA (US); Yu-Huei Lee, New Taipei (TW); and Junjian Zhao, San Jose, CA (US)
Assigned to Monolithic Power Systems, Inc., Kirkland, WA (US)
Filed by Monolithic Power Systems, Inc., Kirkland, WA (US)
Filed on Jun. 28, 2023, as Appl. No. 18/343,446.
Prior Publication US 2023/0397311 A1, Dec. 7, 2023
Int. Cl. H05B 45/30 (2020.01); H05B 45/345 (2020.01); H05B 45/395 (2020.01); H05B 45/46 (2020.01)
CPC H05B 45/345 (2020.01) [H05B 45/395 (2020.01); H05B 45/46 (2020.01)] 19 Claims
OG exemplary drawing
 
1. A Light Emitting Diode (LED) driving circuit for driving an LED string, comprising:
a first current source coupled in series with a heat dissipation resistor, wherein the first current source is configured to provide a first current path to the LED string;
a second current source coupled in parallel with the serially coupled first current source and the heat dissipation resistor, wherein the second current source is configured to provide a second current path to the LED string;
a current sensing circuit configured to sense a current sense signal representing a current flowing through the LED string, wherein the current flowing through the LED string is supplied by the first current path and the second current path; and
a control circuit configured to receive the current sense signal, and control a current distribution of the first current path and a second current path in response to the current sense signal;
wherein when the current sense signal is greater than a threshold, a current flowing through the first current path is larger than a current flowing through the second current path; and
wherein when the current sense signal is less than the threshold, the current flowing through the first current path is less than the current flowing through the second current path.