Patent ID: 8866538
Filing Date: 2014-10-21
Classification: G05F,H02M

Abstract:
1. A constant current circuit comprising: a power supply voltage source; a load including one end coupled to the power supply voltage source; a heat control portion coupled between the other end of the load and a first end of a ground connection resistor, the ground connection resistor having a second end coupled to a ground, the heat control portion configured to suppress a thermal runaway phenomenon of the constant current circuit; a first transistor coupled to the other end of the load in parallel to the heat control portion and configured to increase current efficiency of the heat control portion; and a second transistor configured to switch based on a node voltage at a node coupled to the first end of the ground connection resistor to maintain a level of a current flowing to the ground connection resistor substantially constant, the second transistor being coupled between the ground connection resistor and the first transistor.