CN204178263U - A kind of circuit structure improving input port anti-interference - Google Patents

Abstract

The utility model discloses a circuit structure for improving the anti-interference performance of an input port, which comprises a power supply, a signal input terminal and a Schmidt circuit. The power supply is connected to the power supply input terminal of the Schmidt circuit through an RC filtering structure. The RC filter structure includes a resistor and a capacitor, one end of the resistor is connected to a power supply, the other end of the resistor is respectively connected to the power input end of the Schmitt circuit and one end of the capacitor, and the other end of the capacitor is grounded, The signal input is connected to a Schmidt circuit. The utility model can effectively eliminate the interference on the power supply, has simple structure and low manufacturing cost.

Description

A Circuit Structure for Improving Anti-interference of Input Port

technical field

The utility model relates to an input port circuit of an integrated circuit, in particular to a structure for improving the anti-interference performance of the input port of the integrated circuit.

Background technique

In the design of integrated circuits, the anti-interference of the circuit is very important, and the interference generally enters the chip from the power supply and input port. There are many existing methods to improve anti-interference, the main method is to increase the capacitance filter circuit, reduce the amplitude of the interference signal, and add a Schmitt circuit to the input port, as shown in Figure 1, Vdd is the power supply of the Schmitt trigger , the input signal goes through the Schmidt circuit to the internal circuit of the chip, which can eliminate the interference signal on the input port, but there is a problem here, if there is interference on the power supply Vdd, even if the input signal is good, the interference signal on the power supply will pass through The Schmidt circuit enters the chip and interferes with the normal trigger or distorts the signal. Therefore, it is necessary to further improve the existing anti-jamming circuit.

Contents of the invention

The purpose of this utility model is to provide a circuit structure that improves the anti-interference performance of the input port. By adding an RC structure to the power supply of the input port, the interference on the power supply can be effectively eliminated. The structure is simple and the manufacturing cost is low.

In order to achieve the purpose of the above invention, the technical solution adopted by the utility model is: a circuit structure for improving the anti-interference of the input port, including a power supply, a signal input terminal and a Schmidt circuit, and the power supply is connected to the The power input terminal of the Schmidt circuit, the RC filter structure includes a resistor and a capacitor, one end of the resistor is connected to the power supply, and the other end of the resistor is respectively connected to the power input terminal of the Schmidt circuit and the capacitor. One end, the other end of the capacitor is grounded, and the signal input end is connected to a Schmidt circuit.

Due to the application of the above-mentioned technical solutions, the utility model has the following advantages compared with the prior art:

1. This utility model adds an RC structure to the power supply of the input port, which can well eliminate the interference on the power supply, and has a simple structure and low manufacturing cost.

2. Since the Schmidt circuit is a CMOS structure, CMOS has no static current, so the power consumption is almost zero, that is, there will be no large current on the RC structure to form a voltage drop and reduce the operating voltage range of the input port. Therefore, the RC filter structure is adopted While eliminating interference on the power supply, it can also provide a stable power supply voltage for the Schmidt circuit.

Description of drawings

FIG. 1 is a schematic structural diagram of an existing anti-interference circuit in the background art.

Fig. 2 is a schematic structural diagram of the anti-jamming circuit of the present invention in the first embodiment.

Fig. 3 is a schematic diagram of the application of the utility model in the first embodiment.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Embodiment 1: Referring to Fig. 2, a circuit structure for improving the anti-interference of the input port includes a power supply, a signal input terminal and a Schmidt circuit, and the power supply is connected to the Schmidt circuit through an RC filter structure Power input terminal, the RC filter structure includes a resistor and a capacitor, one end of the resistor is connected to the power supply, and the other end of the resistor is respectively connected to the power input terminal of the Schmidt circuit and one end of the capacitor, the capacitor The other end of the signal is grounded, and the signal input end is connected to a Schmidt circuit.

In this embodiment, the power supply only supplies power to the Schmidt circuit. Since the Schmidt circuit is a CMOS structure, the CMOS has no static current, so the power consumption is almost zero, that is to say, there will be no large current on the RC structure to form a voltage drop. And reducing the operating voltage range of the input port can provide a stable power supply voltage for the Schmidt circuit.

As shown in Figure 3, it is one of the application schemes of this embodiment. In an LED constant current driver chip, Vdd is the power supply of the chip, and the LED grayscale control signal is input from the Pad port, and the Schmitt trigger It can effectively eliminate the interference from the Pad port, and the patented circuit can also effectively eliminate the interference from the power supply Vdd. The gray signal after the noise elimination controls the duty cycle of the PWM, and drives the external LED constant current through the output drive circuit. . Adopting this patented technology can effectively eliminate the interference of the port and the power supply, and ensure the stable operation of the constant current drive circuit.

Claims (1)

1. A circuit structure improving the anti-interference of the input port, comprising a power supply and a signal input terminal, characterized in that: it also includes a Schmidt circuit, and the power supply is connected to the power input of the Schmidt circuit through an RC filtering structure The RC filtering structure includes a resistor and a capacitor, one end of the resistor is connected to the power supply, the other end of the resistor is respectively connected to the power input end of the Schmidt circuit and one end of the capacitor, and the other end of the capacitor is One end is grounded, and the signal input end is connected to a Schmidt circuit.