Patent ID: 9198247
Filing Date: 2015-11-24
Classification: H05B,Y02B

Abstract:
1. A driving device that is used together with a light source and configures a vehicle lamp, the device comprising: a DC/DC converter that receives an input voltage and supplies a drive voltage to the light source; and a controller that controls the DC/DC converter, wherein the DC/DC converter includes: an input terminal, an output terminal, and a ground line; a switching transistor and an input inductor that are provided in series between the input terminal and the ground line; and an output inductor, and wherein the controller includes: a current controller that compares a first coil current which flows in the output inductor with a first upper threshold value and a first lower threshold value; a current limiter that compares a second coil current which flows in the input inductor with a second upper threshold value and a second lower threshold value; and a duty controller that, (i) in a cycle where the first coil current exceeds the first upper threshold value before the second coil current exceeds the second upper threshold value, (i-a) turns OFF the switching transistor triggered by the fact that the first coil current exceeds the first upper threshold value, and (i-b) turns ON the switching transistor triggered by the fact that the first coil current comes below the first lower threshold value, and (ii) in a cycle where the second coil current exceeds the second upper threshold value before the first coil current exceeds the first upper threshold value, (ii-a) turns OFF the switching transistor triggered by the fact that the second coil current exceeds the second upper threshold value, and (ii-b) turns ON the switching transistor triggered by the fact that the second coil current comes below the second lower threshold value.