TI公司的TIC12400-Q1是用在12V汽車系統(tǒng)的24路輸入多路開關(guān)檢測接口（MSDI）器件，集成了10位ADC來檢測模擬開關(guān)多種位置，集成的比較器用來檢測MCU的數(shù)字開關(guān)，檢測閾值可編程，以支持各種開關(guān)拓?fù)浜拖到y(tǒng)非理想性，工作溫度–40℃ 到125℃，支持連續(xù)模式和輪詢模式，主要用在12V汽車系統(tǒng)中的車體控制和網(wǎng)關(guān)，汽車照明，加熱和冷卻，電動座椅和鏡子。本文介紹了TIC12400-Q1主要特性，框圖和應(yīng)用電路，以及評估模塊TIC12400 EVM特性，框圖，主板和開關(guān)板電路圖，材料清單。

The TIC12400-Q1 is an advanced Multiple SwitchDetection Interface （MSDI） designed to detectexternal switch status in a 12-V automotive system.The TIC12400-Q1 features an integrated 10-bit ADCto monitor multi-position analog switches and acomparator to monitor digital switches independentlyof the MCU. Detection thresholds can beprogrammed for the ADC and the comparator tosupport various switch topologies and system nonidealities.

The device monitors 24 direct switch inputs，with 10 inputs configurable to monitor switchesconnected to either ground or battery. 6 uniquewetting current settings can be programmed for eachinput to support different application scenarios. Thedevice supports wake-up operation on all switchinputs to eliminate the need to keep the MCU activecontinuously， thus reducing power consumption of thesystem. The TIC12400-Q1 also offers integrated faultdetection， ESD protection， and diagnostic functionsfor improved system robustness. The TIC12400-Q1supports 2 modes of operations： continuous and　polling mode. In continuous mode， wetting current issupplied continuously. In polling mode， wettingcurrent is turned on periodically to sample the inputstatus based on a programmable timer， thus thesystem power consumption is significantly reduced.

TIC12400-Q1主要特性：

? Qualified for Automotive Applications

? AEC-Q100 Qualified With the Following Results：

– Device Temperature Grade 1： –40 ℃ to 125℃ Ambient Operating Temperature

– Device HBM ESD Classification Level H2

– Device CDM ESD Classification Level C4B

? Designed to Support 12-V Automotive Systemswith Over-voltage and Under-voltage Warning

? Monitors up to 24 Direct Switch Inputs with 10Inputs Configurable to Monitor Switches

Connected to Either Ground or Battery

? Switch Input Withstands up to 40 V （Load DumpCondition） and down to –24 V （Reverse PolarityCondition）

? 6 Configurable Wetting Current Settings：（0 mA， 1 mA， 2 mA， 5 mA， 10 mA， and 15 mA）

? Integrated 10-bit ADC for Multi-Position AnalogSwitch Monitoring

? Integrated Comparator with 4 ProgrammableThresholds for Digital Switch Monitoring

? Ultra-low Operating Current in Polling Mode：

68 μA Typical （tPOLL = 64 ms， tPOLL_ACT = 128 μs，All 24 Inputs Active， Comparator Mode， AllSwitches Open）

? Interfaces Directly to MCU Using 3.3 V/5 VSerial Peripheral Interface （SPI） protocol

? Interrupt Generation to Support Wake-UpOperation on All Inputs

? Integrated Battery and Temperature Sensing

? ±8 kV Contact Discharge ESD Protection on InputPins per ISO-10605 With Appropriate ExternalComponents

? 38-Pin TSSOP Package

TIC12400-Q1應(yīng)用：

? Body Control Module and Gateway

? Automotive Lighting

? Heating and Cooling

? Power Seats

? Mirrors

圖1.TIC12400-Q1框圖

圖2.TIC12400-Q1簡化電路圖

圖3.TIC12400-Q1在12V汽車系統(tǒng)應(yīng)用電路圖

圖4.TIC12400-Q1在車體控制模塊的應(yīng)用電路圖

評估模塊TIC12400 EVM

The TIC12400 is a multiple switch detection interface that is designed to detect the opening and closing ofup to 24 switch contacts. 10 out of the 24 inputs are configurable to detect switch states that are eitherbattery connected switches （BCS） or ground connected switches （GCS）， which means it can either sink orsource current from the channel. The remaining 14 channels are design to support ground connectedswitches only （source current）。 The wetting current can be preprogrammed to six available values， whichaccommodates for different application scenarios. Communication to and from the device is done using a24-bit SPI protocol.

The TIC124000 and TIC12400-Q1 provide the same functionality and the TIC12400 Evaluation Module isused for both devices.

圖5.評估模塊TIC12400 EVM框圖

圖6.評估模塊TIC12400 EVM，開關(guān)板和USB-US－Mini電纜外形圖

圖7.評估模塊TIC12400 EVM主板電路圖（1）：頁連接器

圖8.評估模塊TIC12400 EVM主板電路圖（2）：主器件

圖9.評估模塊TIC12400 EVM主板電路圖（3）：USB接口

圖10.評估模塊TIC12400 EVM主板電路圖（4）：標(biāo)簽

圖11.評估模塊TIC12400 EVM主板電路圖（5）：輸入濾波器-IN10-IN23用10 Ω替代220 Ω

圖12.評估模塊TIC12400 EVM開關(guān)板電路圖

主板材料清單：

開關(guān)板材料清單：