| 摘要 |
PURPOSE:To decrease the number of circuit elements by using a depression type MOSFET to constitute a constant current source and supplying the constant current to an enhancement type MOSFET. CONSTITUTION:An MOSFETQ1 has a depression type function and therefore N<+> is doped as the 1st conduction type impurity to a poly-silicon layer forming a gate electrode of the FETQ1. While P<+> is doped as the 2nd conduction type impurity to a poly-silicon layer forming a gate electrode of an MOSFETQ2 which functions as an enhancement type. The constant current produced by the FETQ1 is supplied to the FETQ2. For this purpose, a series connection is formed as shown in the diagram. Then the reference voltage Vref is obtained from the gate and the source of the FETQ2. |
