JPS6449318A - Analog switch circuit - Google Patents

Abstract

PURPOSE:To prevent the inversion of a switching sequence of a transistor and to execute an exact switching control by making the timing of cut-off in an npn type transistor and a pnp type transistor for constituting an output circuit different from each other. CONSTITUTION:A timing circuit 5 generates a timing signal for control transistors(TRs) Q3, Q6, TRs Q4, Q5, respectively, by allowing it to have a necessary time difference, at the time of A/D and D/A, based on a sample-hold pulse. The control of ON/OFF of an npn type TR Q1 is executed, based on the control of the TRs Q4, Q5, and the control of ON/OFF of a pnp type TR Q2 is executed by an exclusive cut-off means, respectively, based on the control of the TR Q6. Also, said timing of ON/OFF can be determined in advance by the timing circuit 5. In such a way, from a base voltage of the TRs Q1, Q2 of an output circuit at the time of the sample-hold of A/D and the timing of cut-off, the pnp type TR Q2 is cut off by preceding by about 200ns with respect to the npn type TR Q1.