US Patent No. 10,512,130

MULTI-STRING LED DRIVERS AND CURRENT SWITCHING TECHNIQUES


Patent No. 10,512,130
Issue Date December 17, 2019
Title Multi-string Led Drivers And Current Switching Techniques
Inventorship Erhan Ozalevli, Santa Clara, CA (US)
Behzad Mohtashemi, Campbell, CA (US)
Assignee Apple Inc., Cupertino, CA (US)

Claim of US Patent No. 10,512,130

1. A circuit comprising:a first source;
a second source;
a set of drivers, each of the set of drivers comprising:
a set of first transistors, each first transistor coupled to a pulse-width modulation (PWM) signal;
a first resistor;
a second transistor, the second transistor coupled to the set of first transistors and the first resistor;
a third transistor, the third transistor coupled to the second transistor and the second source; and
an operational amplifier coupled to the second transistor; and
a set of strings of series-connected light emitting diodes (LEDs), wherein the set of strings of series-connected LEDs is coupled to the set of drivers and the first source, such that a respective one of the set of drivers is configured to connect to any one of the set of strings of series-connected LEDs.