DEVICE FOR PROVIDING SUBSTANTIALLY CONSTANT CURRENT IN RESPONSE TO VARYING VOLTAGE

摘要

PURPOSE: A device is provided to uniformly maintain a drain current when the voltage of a power supply is changed by including a plurality of current mirrors. CONSTITUTION: A first current mirror(310) receives a first amount of a first bias current(IBIAS1). The first current mirror offers an output current based on the first amount of the first bias current. A second current mirror(330) receives a second first bias current and a second amount of a first bias current. The second amount of the second bias current bases on the variable voltage from a second voltage source. The first current mirror comprises a first transistor(311) and a second transistor(312). The first amount of the first bias current comprises the drain current of the first transistor.