A two-port input control circuit with Schmitt characteristics to suppress temperature drift

Abstract

The invention discloses a novel double-port input control circuit with a temperature drift suppressing property and a Schmidt property. The circuit consists of a temperature drift suppressing circuit and a window circuit and can be used in the internal or external part of a transformer isolated or photo-isolated solid relay as a control drive of the preceding stage. With the mutual suppression of a triode, the control circuit realizes the temperature drift resisting function through utilizing a current feedback function and ensures connection of the solid relay and relative stable of the closed threshold voltage; meanwhile, the control circuit realizes overturning of the output voltage through utilizing the reversal function of the triode; and the control circuit realizes the window property, namely the Schmidt property of the connected voltage and turnoff voltage of the solid relay through the negative feedback formed by a resistor. Compared with the traditional temperature suppression circuit, the input function of the Schmidt property is increased, so that the problem that the PN junction voltage input in a control apparatus is changed with the change of the environment temperature is solved, and stable input and reliable application of the solid relay in the total temperature operating scope are ensured.

Description

technical field [0001] The present invention relates to a control circuit, more specifically, to a two-port input control circuit with Schmitt characteristics for suppressing temperature drift, which can be used in the control circuit of solid state relays. Background technique [0002] Generally, solid state relays with two-port input and transformer isolation use transistors as input control devices. The disadvantage of this kind of device is that it is very sensitive to ambient temperature, and in a wide operating temperature range (such as -55°C to 125°C), it may cause device control failure, and in severe cases, it will be destroyed. Therefore, a variety of circuits for suppressing temperature drift have been developed in the prior art to compensate or suppress this kind of drift, so as to ensure effective control within the entire operating temperature range. [0003] Among the temperature drift suppression circuits that have been applied at present, some use temperat...

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Problems solved by technology

[0007] Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a novel two-port input control circuit with Schmitt characteristics for suppressing temperature drift. The control circuit only uses NPN transistors, PNP transistors and resistors to form a temperature suppression circuit, which can Solve problems such as high requirements for two-port input, difficulty in miniaturization and integration, temperature drift, and no Schmitt input characteristics

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