Display apparatus, driving apparatus for light-emitting devices, and image forming apparatus

A method for driving a light-emitting device that uses a transistor, one of a source and a drain of which is connected to a power source and another of which supplies current to the light-emitting device, and a non-inverting voltage amplifier that outputs voltage determined by voltage at an input terminal, the method comprising:

• a first step in which a threshold voltage of the transistor is set between a gate and the source of the transistor by connecting the source or the drain of the transistor that supplies the current to the light-emitting device to an end of a capacitor to supply a current from the transistor to the capacitor and transferring a voltage of the capacitor to the gate of the transistor through the non-inverting voltage amplifier until the current becomes zero;
• a second step in which the threshold voltage set between the gate and the source of the transistor is changed according to data voltage by disconnecting the transistor from the one end of the capacitor and applying the data voltage to another end of the capacitor;
• and
• a third step in which the light-emitting device is caused to light at luminescence according to the data voltage by connecting the source or the drain of the transistor to the light-emitting device, and supplying the current flowing through the transistor to the light-emitting device.

A driving apparatus for light-emitting devices, the driving apparatus comprising:

• a plurality of transistors configured to be arranged in a row direction and a column direction, each of the plurality of transistors including a source and a drain, one of which is connected to a power supply and another of which supplies current to each of the light-emitting devices;
• data lines configured to be provided for the plurality of transistors in the column direction in common and connected to gates of the transistors through first switches;
• feedback lines configured to be provided for the plurality of transistors in the column direction in common and connected to the source or the drain of the transistors that supplies the current to each of the light-emitting devices through second switches;
• third switches configured to connect the source or the drain of the transistors to the light-emitting devices to supply currents;
• a voltage amplifier, an input terminal of which is connected to one of the feedback lines through a fourth switch and an output terminal of which is connected to one of the data lines;
• and
• a data generation circuit configured to be connected to the input terminal of the voltage amplifier via a capacitor connected in series,
• wherein the voltage amplifier is a non-inverting voltage amplifier to transfer a change in voltage at the input terminal to the output terminal without changing polarity, and converts a change in voltage of the corresponding feedback line generated by a current flowing from the transistors to the capacitor through the second switches into a change in voltage of the corresponding data line in a direction in which the transistors connected to the data line through the first switches turn off.