RU2382489C1 - Switch based on digital mis chip with open drain output - Google Patents

Abstract

FIELD: physics; computer engineering.

SUBSTANCE: invention relates to pulse engineering and can be used in different low-current switching devices where there is need for galvanic isolation of control circuits from output buses, for example in telemetry. The technical result is achieved due to that, the secondary winding of the transformer is made with a centre terminal which is connected to the common power bus of the digital MIS chip with an open drain output, outermost leads of the secondary transformer winding are connected through diodes in the positive polarity to the positive power bus of the digital MIS chip with an open drain output. The beginning of the secondary winding of the transformer is connected through a diode in the positive polarity to the control input of the digital MIS chip with an open drain output. There is a capacity and a resistor which are connected in parallel and connected between the input and the common power bus of the digital MIS chip with an open drain output. There is an additional capacitor which is connected between power buses of the digital MIS chip with an open drain output.

EFFECT: reduced size and mass of the switching device.

1 dwg

Description

The invention relates to a pulse technique and can be applied in various low-current switching devices where galvanic isolation of control circuits from output buses is required, for example, in telemetry.

A known power switch containing an isolation transformer, two complementary bipolar transistors, capacitors, resistors and diodes (High-frequency converters on high-power MOS transistors / B.V. Kabelev. - ETvA, 1984, issue 15, p. 27, Fig. 5) .

However, this switch does not allow switching long pulses.

The closest to the proposed technical essence is the key on the MOS transistor, containing transistors of the same conductivity, the collector-emitter junctions of which are shunted by the diodes in the locking direction, and the base-emitter junctions are resistors, the collector of one of the transistors is connected to the gate of the MOS transistor, the transformer , the emitters of the transistors are connected directly, and the collector of another transistor is connected to the beginning of the secondary winding of the transformer, the end of which is directly connected to the source M DP transistor, in addition, an additional secondary winding is introduced into the transformer with a decreasing transformation coefficient relative to the secondary winding, which is connected to the bases of the transistors, and the beginning of the additional secondary winding is connected to the base of that transistor, the collector of which is connected to the beginning of the transformer secondary winding (RF patent, No. 2263393), which is selected as a prototype.

The disadvantage of the prototype when it is used in low-current switching devices is the need to use a powerful MOS transistor, which has a relatively large size and weight due to the lack of domestic low-power MOS transistors.

The aim of the invention is to reduce the size and weight of the switching device.

This goal is achieved by the fact that the secondary winding of the transformer is made with the output from the midpoint, which is connected to the common power bus of the digital TIR microcircuit with an open drain output, the extreme terminals of the secondary winding of the transformer through diodes in positive polarity are connected to the positive power bus of the digital TIR microcircuit with an open drain output, and the beginning of the secondary winding of the transformer through a diode in positive polarity is connected to the input of a digital MIS chip with an open drain output, introduced a capacitor and a resistor that are connected in parallel and connected between the input and the common power bus of the digital MIS chip with an open drain output, an additional capacitor is introduced, which is connected between the power buses of the digital MIS chip with an open drain output.

The drawing shows a circuit diagram of a key on a digital MIS chip with an open stock output.

The key on the digital MIS chip with an open drain output contains a transformer 1 with a primary winding 2 and a secondary winding 3, with a pin 4 from a midpoint that is connected to a common bus 5 of the microcircuit 6 and the source of the MIS transistor 7 inside the microcircuit 6; the extreme conclusions 8 and 9 of the winding 3 of the transformer 1 through the diodes 10 and 11 in positive polarity are connected to the power output 12 of the chip 6; between the common power bus 5 and the power output 12 of the microcircuit 6, a capacitance 13 is connected, the output 8 (beginning) of the secondary winding 3 through the diode 14 in positive polarity is connected to the input 15 of the microcircuit 6; between the input 15 of the microcircuit 6 and the common bus 5 are connected in parallel connected capacitance 16 and the resistor 17.

The device operates as follows.

When applying to the input of the device on the primary winding 2 of transformer 1 short positive pulses with a high duty cycle, the output 8 of the secondary winding 3 of transformer 1 relative to the midpoint 4 also appears short positive pulses, which through diodes 10 and 14 charge the capacities 13 and 16 to the amplitude value short positive pulses, and since the MIS microcircuit consumes a very small current along the power buses and has a high input impedance, a voltage close to the voltage will be established at the input 15 of the microcircuit 6 power at pin 12 of chip 6, i.e. equal to the voltage of the logical unit, and the MOS transistor 7 inside the chip 6 opens.

When short negative pulses are applied to the input of the device to the primary winding 2 of transformer 1, short negative pulses will appear at terminal 8 of secondary winding 3, and short positive pulses will appear at terminal 9 of secondary winding 3 of transformer 1 relative to midpoint 4, which charge capacitor 13 through diode 11 providing power to the microcircuit 6; the negative pulses from terminal 8 of the secondary winding 3 of transformer 1 will not pass through the diode 14, and the capacitor 16 is discharged through the resistor 17 to a logic zero voltage, and the MOS transistor 7 inside the microcircuit 6 is closed.

The mass and dimensions of the proposed device are smaller than in the prototype due to the smaller mass and dimensions of the microcircuit by 12.5 times (a powerful field-effect transistor 2P762A in the lightest housing of the KT-57 weighs 5 g, and the microcircuit 1526LA10 does not exceed 0.4 g). The advantages of the prototype are preserved - low power along the control circuit and high noise immunity.

The prototype of the device was assembled on a 1526LA10 chip, 2D522B diodes, a TIL2V transformer, a 1 MΩ resistor, a 13 nF capacitor 13, and the input capacitance of the 1526LA10 chip served as a capacitor 16.

When controlling pulses with an amplitude of 9 V, τ = 1 μs, Q = 8, the switch switched 0.1 A with a duration of fronts of 5 μs and a voltage drop of 0.27 V.

Of the patent information materials known to the applicant, no signs were found that are similar to the totality of the features of the claimed object.

Claims (1)

The key on a digital TIR - microcircuit with an open drain output, containing a transformer, diodes, characterized in that the secondary winding of the transformer is made with the output from the midpoint, which is connected to the common power bus of the digital TIR - microcircuit with an open drain output, the extreme terminals of the secondary winding of the transformer through diodes in positive polarity are connected to the positive power bus of the digital MIS - microcircuit with open drain output, while the beginning of the secondary winding of the transformer through the diode in the positive polar connected to the input of the digital TIR - microcircuit with open drain output, a capacitor and a resistor are introduced, which are connected in parallel and connected between the input and the common power bus of the digital TIR - microcircuit with open drain output, an additional capacitor is inserted, which is connected between the power buses of the digital TIR - microchips with open stock output.