SU617840A1 - Analogue switch - Google Patents

Description

one

The invention relates to the field of analog and hybrid computing and information measuring equipment. In particular, it can be used in the construction of time-pulse devices, high-speed electronic switches and a node resistive element of an automated grid integrator.

An analog switch is known that contains a field-effect transistor with a control p-junction, between which two high-resistance linearizing resistors connected in series are connected between the drain and the source. To the midpoint of the latter, the gate of the field-effect transistor is connected via a diode, connected via an oppositely connected diode with a clamp, to which control signal 1 is supplied. source of the field-effect transistor, which reduces its accuracy in the open state.

Also known is an analog switch containing a field-effect transistor with a control p-l junction, a diode and two high-resistance resistors connected to the source and drain of the field-effect transistor 2. Such a switch requires a long switching time for floating-gate circuits and has a relatively low input the resistance is in the "on" state with the communication resistance.

The purpose of the invention is to reduce the error in the open state. To do this, a diode and two field-effect transistors, whose sources are connected to each other and to the gate of the first field-effect transistor, are inserted into the analog switch, the gates are between themselves and with the diode inserted, the drains are connected with resistors, and an additional resistor is connected between the sources and gates.

The drawing shows a schematic diagram of the proposed key. It contains a zero transistor 1 with a control p-junction, two resistors 2, two additional field-effect transistors 3 with a control p-junction and a channel of the same type as that of transistor 1, resistor 4 and diodes 5 and 6.

When applying a positive (in the case of using a field-effect transistor with a / g-type channel) control signal with an amplitude of + f / y higher than the maximum level of the switched signal Uc, diode 5 closes. In this case, the magnitude of the external control signal supplied to the gates of the field effect transistors is zero.

All transistors turn out to be in a closed state, while the conduction of the channel of field-effect transistor 1 is maximum and does not depend on the level of the switched signal, as well as on the polarity of the "drain-source" voltage when its value changes within ± 1 V. The latter is achieved due to supplying a "drain-source" voltage with a voltage divider on high-resistance resistors 2. When a negative control signal is applied - / 7u, the open state of all field-effect transistors is maintained regardless of the voltage level of the switched signal Ala. In this case the condition must be fulfilled:

op g -c.mlI

,, + Е, „,

where Uo is the cutoff voltage at which the field effect transistor is completely closed.

The key error in the open state due to the linearizing circuit formed by resistors 2 and field-effect transistors 3 is eliminated, since the linearizing circuit is also open.

Claims (2)

1. Copyright certificate USSR № 451194, cl. H OZK 17/60, 1972. 2. Totmenin V.F. Analog key on 25 field-effect transistors. Novosibirsk “Science, 1971.