| 摘要 |
PURPOSE:To prevent an output voltage from being decreased rapidly even if an output current is increased by providing the 1st-4th transistors (TRs) and connecting both of a collector of the 1st TR and an emitter of the 3rd TR to an output terminal. CONSTITUTION:When a signal of a low level [below (VCC-VBE)] is applied to an input terminal 1, TRsQ1, Q2 are conductive (saturating state) and an output voltage V0 at an output terminal 2 is V0=VCC-VCE(SAT)Q1 and a current is applied to a load connected to an output terminal 2. When a current I0 is increased, the collector-emitter saturated voltage VCE(SAT)Q1 of the TRQ1 is increased and the output voltage V0 is decreased. When the output voltage V0 becomes VCC-VCE(SAT)Q2-VBE or below, an npn TRQ3, however, starts being conducted, where VCE(SAT)Q2 is a collector-emitter saturated voltage of the TRQ2. Thus, the output voltage is kept to a certain constant voltage even if the output current is increased. |
