Double-frequency-point tire pressure sensor without digital switch

Abstract

The utility model discloses a double-frequency-point tire pressure sensor without a digital switch. The double-frequency-point tire pressure sensor comprises a tire pressure sensor chip; the radio frequency circuit is connected with the tire pressure sensor chip; and the matching circuit comprises a C17 capacitor, one end of the C17 capacitor is connected with the radio frequency circuit, and the other end of the C17 capacitor is connected with the I / O pin of the tire pressure sensor chip. Compared with the prior art, the tire pressure monitoring sensor solves the problem that an existing tire pressure monitoring sensor is complex in circuit design.

Description

Technical Field

[0001] The utility model relates to the technical field of tire pressure sensors, in particular to a dual-frequency tire pressure sensor without a digital switch. Background Art

[0002] Direct tire pressure monitoring sensors use pressure sensors installed in each tire to directly measure tire pressure, and use wireless transmitters (usually at 433MHz or 315MHz) to send pressure information from the inside of the tire to the central receiver module, which then displays the tire pressure data. When the tire pressure is too low or leaking, the system will automatically alarm.

[0003] In the existing tire pressure monitoring sensor circuit design, different frequencies are switched by digital switches, the circuit parameters in the matching network are changed, and different frequency points (433MHz and 315MHz) are adapted. For example, Chinese Patent 202010584078.8 discloses a dual-frequency tire pressure sensor frequency band compatibility method based on a digital switch, which includes the following steps: (1) the output end of the tire pressure sensor is connected to the antenna transmission network; (2) the tire pressure sensor outputs a first frequency signal; (3) the digital switch is closed, and the antenna transmission network performs impedance matching to enter the first capacitance mode; (4) the tire pressure sensor outputs a second frequency signal; (5) the digital switch is opened, and the antenna transmission network performs impedance matching to enter the second capacitance mode. It provides a dual-frequency tire pressure sensor frequency band compatibility method based on a digital switch, which enables an antenna transmission network of the tire pressure sensor to be compatible with the 433.92MHz and 315MHz frequency bands.

[0004] Therefore, the setting of the digital switch makes the tire pressure monitoring sensor circuit design complicated and increases the PCB area. At the same time, one more digital switch is used in the circuit, which increases the unit cost. Utility Model Content

[0005] The purpose of the utility model is to provide a dual-frequency tire pressure sensor without a digital switch to solve the problem of complex circuit design of the existing tire pressure monitoring sensor.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solution: a dual-frequency tire pressure sensor without a digital switch, comprising:

[0007] Tire pressure sensor chip;

[0008] A radio frequency circuit connected to a tire pressure sensor chip;

[0009] The matching circuit includes a C17 capacitor, one end of which is connected to the radio frequency circuit and the other end is connected to the I / O pin of the tire pressure sensor chip.

[0010] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0011] 1. In the present invention, an I / O pin of the tire pressure sensor chip is used to control the on / off of the capacitor in the circuit and the matching parameter changes in the control circuit. The same sensor hardware can support both 433MHz and 315MHz, and while deleting the digital switch, it can meet the dual-frequency transmission and ensure the transmission intensity of the RF transmission power. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 The present invention is a circuit diagram of a dual-frequency tire pressure sensor without a digital switch.

[0014] Legend:

[0015] 1. Tire pressure sensor chip; 2. RF circuit; 3. Matching circuit. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] Example 1

[0018] See also Figure 1 The utility model provides a technical solution: a dual-frequency tire pressure sensor without a digital switch, comprising:

[0019] Tire pressure sensor chip 1;

[0020] A radio frequency circuit 2 connected to the tire pressure sensor chip 1;

[0021] The matching circuit 3 includes a C17 capacitor, one end of which is connected to the RF circuit 2 and the other end of which is connected to the I / O pin of the tire pressure sensor chip 1 .

[0022] Use an I / O pin of the tire pressure sensor chip 1 to control the on / off of the capacitor in the circuit and the matching parameter changes in the control circuit. The same sensor hardware can support 433MHz and 315MHz at the same time. While removing the digital switch, it can meet the dual-frequency transmission and ensure the transmission intensity of the RF transmission power. It only needs to use the existing I / 0 port of the tire pressure sensor chip 1 and add control logic to the program. No additional circuit design is required, which reduces PCB design layout and reduces costs.

[0023] Working principle: C17 capacitor is in matching circuit 3. By controlling the level attribute of GPIO5, whether C17 capacitor works or not is controlled.

[0024] When sending 433MHz, the tire pressure sensor chip 1 controls the I / O port to set a long low level. At this time, the C17 capacitor is equivalent to grounding and is connected in parallel to GND together with C14 in the circuit;

[0025] When sending 315MHz, the tire pressure sensor chip 1 controls the I / O port to high impedance, and the C17 capacitor does not work.

[0026] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A dual-frequency tire pressure sensor without a digital switch, characterized in that: include: Tire pressure sensor chip; A radio frequency circuit connected to the tire pressure sensor chip; The matching circuit includes a C17 capacitor, one end of which is connected to the radio frequency circuit and the other end of which is connected to the I / O pin of the tire pressure sensor chip.

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