Display device, detecting method and pixel driving circuit

A detecting method, comprising:

• writing a first reference signal through a first switch into a control terminal of the first switch at a first node;
• after writing the first reference signal into the control terminal of the first switch, writing a data signal through a first capacitor into the first node;
• generating a first current flowing through the first switch;
• measuring the first current;
• and
• determining the first switch being normal, in response to a current level the first current corresponding to the data signal,
• wherein writing the first reference signal comprises writing the first reference signal through a first terminal of the first switch and a second terminal of the first switch in order, and
• the control terminal of the first switch, the first terminal of the first switch and the second terminal of the first switch are different from each other.

A pixel driving circuit comprising:

• a first switch configured to generate a current according to a voltage level of a first node, a control terminal of the first switch being coupled to the first node;
• and a second switch, a first terminal of the second switch being coupled to the first node, a second terminal of the second switch being coupled to a first terminal of the first switch at a second node;
• a third switch, a control terminal of the third switch being configured to receive a light emitting signal, a first terminal of the third switch being coupled to the second node;
• a fourth switch, a control terminal of the fourth switch being configured to receive the light emitting signal, a first terminal of the third switch being coupled to a second terminal of the first switch at a third node;
• a light emitting element configured to receive the current to emit light;
• and a data writing unit coupled to the first node and the third node, and configured to adjust the voltage level of the first node, wherein the first switch is configured to adjust a voltage level of the first node according to a scan signal which is received by a control terminal of the first switch, and the control terminal of the first switch is different from the first terminal of the first switch.