Pixel driver circuit with load-balance in current mirror circuit

摘要

A pixel circuit for use in a display comprising a plurality of pixels is provided. The load-balanced current mirror pixel circuit can compensate for device degradation and/or mismatch, and changing environmental factors like temperature and mechanical strain. The pixel circuit comprises a pixel drive circuit comprising, switching circuitry, a current mirror having a reference transistor and a drive transistor, the reference transistor and the drive transistor each having a first and second node and a gate, the gate of the reference transistor being connected to the gate of the drive transistor; and a capacitor connected between the gate of the reference transistor and a ground potential, and a load connected between the current mirror and a ground potential, the load having a first load element and a second load element, the first load element being connected to the first node of the reference transistor and the second load element being connected to the first node of the drive transistor.

主权项

1. A pixel driver circuit for use in a display, comprising:
switching circuitry for providing a reference current input, the switching circuitry including:
a switch transistor having a gate connected to a first select line, a first terminal connected to a data line, anda feedback transistor having a gate connected to a second select line, a first terminal connected to a second terminal of the switch transistor; a light emitting device having a first terminal and a second terminal, the second terminal being connected to a first potential; and a current mirror for providing a drive current to the light emitting device based on the reference current, the current mirror including:
a drive transistor for conveying the drive current through the light emitting device and having a first node;a reference transistor for receiving the reference current, the reference transistor having a gate connected to a gate of the drive transistor, the reference transistor having a drain terminal connected either to a second terminal of the feedback transistor or to a second terminal of the switch transistor, wherein the first terminal of the light emitting device is connected to the first node and to a source terminal of the reference transistor; anda capacitor for storing a program voltage independent of a transistor threshold voltage, the program voltage settling on the capacitor while the reference current is conveyed through the reference transistor, the capacitor having a first terminal connected to both the gate of the drive transistor and the gate of the reference transistor, the capacitor having a second terminal connected to the first potential.