Current source device for electrostatic discharge and display device including the same

A display device comprising:

• a signage including an LED string configured to operate using a current supplied from a power supply;
• and
• a current source device configured to control an amount of the current supplied from the power supply to the LED string,
• wherein the current source device includes:
• a sourcing circuit including a first MOS transistor configured to transmit a current flowing from a pad to a first node in response to a current control voltage, and a second MOS transistor configured to transmit the current flowing from the first node to a ground in response to a bias voltage;
• a control circuit including an amplifier configured to generate the current control voltage based on a setting voltage applied from an outside and a voltage of the first node, a first resistor disposed between an output terminal of the amplifier and a gate terminal of the first MOS transistor, and a first switch configured to transmit the bias voltage to a gate terminal of the second MOS transistor in response to a switching control signal;
• and
• a discharge circuit configured to discharge a current corresponding to static electricity flowing from the first node to the ground,
• wherein the current flowing from the pad contains the current corresponding to the static electricity,
• wherein a withstand voltage of the first MOS transistor is higher than a withstand voltage of the second MOS transistor,
• wherein the discharge circuit includes a third MOS transistor, and
• wherein a gate terminal of the third MOS transistor is connected to a second node, and one terminal of the third MOS transistor is connected to the first node and another terminal of the third MOS transistor is connected to the ground.

A display device comprising:

• one or more current source devices, wherein each of the one or more current source devices includes:
• a sourcing circuit including a first MOS transistor configured to transmit a current flowing from a pad to a first node in response to a current control voltage, and a second MOS transistor configured to transmit the current flowing from the first node to a ground in response to a bias voltage;
• a control circuit including an amplifier configured to generate the current control voltage based on a setting voltage applied from an outside and a voltage of the first node, a first resistor disposed between an output terminal of the amplifier and a gate terminal of the first MOS transistor, and a first switch configured to transmit the bias voltage to a gate terminal of the second MOS transistor in response to a switching control signal;
• a selection unit configured to control a discharge function of the one or more current source devices;
• and
• a discharge circuit configured to discharge a current corresponding to static electricity flowing from the pad to the ground,
• wherein a withstand voltage of the first MOS transistor is higher than a withstand voltage of the second MOS transistor,
• wherein the discharge circuit includes a third MOS transistor and a third resistor,
• wherein one terminal of the third MOS transistor is connected to the first node, and another terminal of the third MOS transistor is connected to the ground, and
• wherein one terminal of the third resistor is connected to a gate terminal of the third MOS transistor and another terminal of the third resistor is connected to the ground.