AN238 Datasheet, PDF (1/12 Pages) Microchip Technology – Tire Pressure Monitoring (TPM) System

AN238
Tire Pressure Monitoring (TPM) System
Authors: Ruan Lourens
Microchip Technology Inc.
Curtis Kell
Kell Laboratories
INTRODUCTION
This document explains a typical tire pressure monitor-
ing (TPM) system specifically intended for automotive
use. It serves as a reference to design a real-world
system based on various Microchip products. A TPM
system primarily monitors the internal temperature and
pressure of an automobile's tire. There is a variety of
system approaches to follow, although this one is a
rather comprehensive auto-location system.
An auto-location system can dynamically detect the
position of a specific sensor, which is useful when tires
are rotated. The heart of the TPM system is the
Sensor/Transmitter (S/TX) device and it is based on
Microchip's rfPIC12F675.
SYSTEM COMPONENTS
The TPM system consists of the following major
component.
• Sensor/Transmitter Device
• RF Receiver Module
• Low Frequency (LF) Commander Device
• Control Unit
• Pressure Vessel (Tire)
FIGURE 1:
TIRE PRESSURE MONITORING (TPM) SYSTEM
 2004 Microchip Technology Inc.
DS00238B-page 1