Micro-led systems having in situ current measurement circuits

A method for in situ measurement of current associated with one or more micro-LEDs in a micro-LED system comprising:

• (1) a set of micro-LEDs formed in a display substrate, and (2) a set of pixel driver circuits formed in a backplane substrate coupled to the display substrate, wherein each of the set of pixel driver circuits is to provide current to a respective one of the set of micro-LEDs during a normal mode of operation for the set of micro-LEDs, the method comprising:
• using a set of pass transistors, during a test mode of operation, on a per pixel driver circuit basis, redirecting current from one or more of the set of pixel driver circuits to a current measurement circuit;
• and
• using the current measurement circuit, performing an in situ measurement of the redirected current within the backplane substrate, wherein the current measurement circuit comprises an operational amplifier configured to drive a source-follower transistor.

A micro-LED system comprising:

• a set of micro-LEDs formed in a display substrate;
• a set of pixel driver circuits formed in a backplane substrate coupled to the display substrate, wherein a respective pixel driver circuit is to provide current to a respective micro-LED during a first mode of operation for the set of micro-LEDs;
• a set of pass transistors to, during a second mode of operation, different from the first mode of operation, on a per pixel driver circuit basis, selectively redirect current from one or more of the set of pixel driver circuits to a current measurement circuit, formed in the backplane substrate, allowing for in situ measurement of the redirected current within the backplane substrate;
• and
• wherein the current measurement circuit comprises:
• (1) an operational amplifier configured to drive a source-follower transistor, (2) a level translation and scaling circuit coupled to the source-follower transistor, and (3) an analog to digital converter (ADC) coupled to the level translation and scaling circuit, wherein the level translation and scaling circuit is configured to scale voltage levels for coupling with the ADC.