Patent ID: 8471478

Claim:
A light control signal generating circuit comprising: a photosensitive element for receiving ambient light; two transistors; and four resistances; wherein a first resistance and the photosensitive element are connected in series between a power voltage terminal and a ground terminal, a base electrode of a first transistor is connected to a node between the first resistance and the photosensitive element, a collecting electrode of the first transistor is connected to the power voltage terminal through a second resistance, an emitting electrode of the first transistor is connected to the ground terminal through a third resistance, a base electrode of a second transistor is connected to a node between the second resistance and the first transistor, a collecting electrode of the second transistor is connected to the power voltage terminal through a fourth resistance, an emitting electrode of the second transistor is connected to the ground terminal through the third resistance, and an output terminal is formed from a node between the fourth resistance and the second transistor.