方案概述

　　中低端数字指针汽车仪表盘由各种仪表、警示灯和蜂鸣报警器等组成，为驾驶员提供所需的车速里程、转速、机油压力、水温、燃油和蓄电池等行车信息。本方案中低端数字仪表盘采用单芯片实现LCD显示和仪表指针控制，集成了CAN网络功能和报警控制功能，可以清晰地输出驾驶员所需的信息和警告指示。

　　优势

　　• 高集成度16位MCU(RL78/D1A)具有32MHz主频，集成步进电机控制器、声音发生器和段码LCD控制器，简化仪表外围电路，单芯片即可实现汽车仪表控制。

【RL78/D1A】

Microcontrollers for automotive low-end instrument clusters with built-in features such as sound generator, stepper motor controller/driver, and segmented LCD driver

RL78/D1A microcontrollers have a built-in sound generator which can set a volume level and tone frequency of 100 Hz to 6 kHz and has an automatic volume decrement function, up to four channels of stepper motor controller/driver which can set an 8-bit precision (pseudo 9-bit precision using a 1-bit addition function) pulse width (PWM output), and an LCD controller/driver which supports up to 216 segments. The 128-pin version has a built-in LCD bus interface and two channels of CAN, and expanded flash memory/RAM up to a maximum of 512 KB/24 KB, making these microcontrollers ideal for low-end instrument cluster.

Key Features:

Pin Count / Memory Size Lineup:

Program Flash
SRAM　 　 　 　

Block Diagram:

　　• 高耐压LDO(R1524x)，耐压达50V，输出电流为200mA，可用于仪表盘一次性电源12转5V;高精度(±0.6%输出电压)，用于电压参考，可提高仪表数据信号采集精度。

【R1524x】

OUTLINE

The R1524x is an ultra-low supply current volta ge regulator featuring 200 mA output current and 36 V input voltage. T his device co nsists of an Outpu t Short-cir cuit Protect ion Circuit, an Over-current Protect ion Circuit , and a Thermal Shutdown Circuit in addition to the basic regulator circuits. The operating temperature range is from −40°C to 105°C, and the maximum input voltage is 36 V. All these features allow the R1524x to become an ideal power source of electric home appliances. The outpu t v olt ages are int er nal ly fixed at e ither of the f ollo wing : 1. 8 V, 2.5 V, 2.8 V, 3.0 V, 3.3 V, 3.4 V, 5.0 V, 5.5 V, 6.0 V, 6.4 V, 8.0 V, 8.5 V and 9.0 V. The output voltage accuracy is ±0.6%. The pac kages f or this device range from high-densit y mounting to ultra high watt age. The R1524x is offered in five pac kages; a 5-pin SO T-23-5, a 5-pin SOT-89-5, a 6-pin HSOP-6J, a 6-pin DFN(PLP)1820-6, and an 8-pin HSOP-8E package.

FEATURES ●Input Vol tage Range (Maximum Rating) ····3.5 V to 36 V (50 V)

●Operating Temperature Range ···· −40°C to 105°C

●Supply Current ··· Typ. 2.2 µA

●Standby Current ··· Typ. 0.1 µA

●Dropout Voltage ··· Typ. 0.6 V (IOUT = 200 mA, VOUT = 5.0 V)

●Output Voltage Range ·1.8 V / 2.5 V / 2.8 V / 3.0 V / 3.3 V / 3.4V /5.0 V / 5.5 V / 6.0 V / 6.4 V / 8.0 V / 8.5 V / 9.0 V *Contact Ricoh sales representatives for other voltages.

●Output V oltage Accuracy ···· ±0.6% (Ta = 25°C)

●Output Voltage Temperature-Drift Coefficient ··· Typ. ±60 ppm/°C

●Line Regulation ····· Typ. 0.01%/V (VSET + 1 V ≤ VIN ≤ 36 V)

●Built-in Output Short-cir cuit Pr otection Circui t ··· Typ. 80 mA

●Built-in Over-current Protection Circuit ··· Typ. 350 mA

●Built-in Thermal Shutdown Circuit ··· Thermal Shutdown Temperature: Typ. 160°C

●Ceramic capacitors are recommendedto be used with this device ···COUT = 0.1 μF or more

●Packages ··· SOT-23-5, SOT-89-5, HSOP-6J,DFN(PLP)1820-6, HSOP-8E

APPLICATIONS ●Power source for home appliances such as refrigerators, rice cookers, and electric hot-water pot.

●Power source for notebook PCs, digital TVs, cordless phones, and private LAN system.

       ●Power source for office equipment machines such as copiers, printers, facs im iles, s c anners, and proj

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       【汽车仪表盘】

　　汽车仪表盘是反映车辆各系统工作状况的装置。常见的有燃油指示灯、清洗液指示灯、电子油门指示灯、前后雾灯指示灯及报警灯。

　　不同汽车的仪表不尽相同。但是一般汽车的常规仪表有车速里程表、转速表、机油压力表、水温表、燃油表、充电表等。

　　现代汽车仪表盘的面膜下制作了各式各样的指示灯或警报灯，例如冷却液液面警报灯、燃油量指示灯、清洗器液面指示灯、充电指示灯、远近光变光指示灯、变速器挡位指示灯、制动防抱死系统(ABS)指示灯、驱动力控制指示灯、安全气囊(SRS)警报灯等。

　　车速里程表实际上由两个表组成。一个是车速表，另一个是里程表。

　　传统的车速表是机械式的。典型的机械式里程表连接一根软轴.软轴内有一根钢丝缆。软轴另一端连接到变速器某一个齿轮上。齿轮旋转带动钢丝缆旋转.钢丝缆带动里程表罩圈内一块磁铁旋转。罩圈与指针联接并通过游丝将指针置于零位。磁铁旋转速度的快慢引起磁力线大小的变化。平衡被打破指针因此被带动。这种车速里程表简单实用.被广泛用于大小型汽车上。不过.随着电子技术的发展。现在很多轿车仪表已经使用电子车速表，常见的一种是从变速器上的速度传感器获取信号，通过脉冲频率的变化使指针偏转或者显示数字。

　　里程表是一种数字式仪表，它通过计数器鼓轮的传动齿轮与车速表传动轴上的蜗杆啮合，使计数器鼓轮转动。其特点是上一级鼓轮转一整圈。下一级鼓轮转1/10圈。同车速表一样，目前里程表也有电子式里程表，它从速度传感器获取里程信号。电子式里程表累积的里程数字存储在非易失性存储器内，在无电状下态数据也能保存。

　　机油压力表的传感器是一种压阻式传感器。用螺纹固连在发动机机油管路上。由机油压力推动接触片在电阻上移动，使阻值变化从而影响到通过仪表到地的电流量。驱动指针摆动。由于机油压力有一定的压力范围，为了清晰明了。目前有许多汽车的机油压力表用指示灯表示。如果发动机运转时它仍然亮着。就表示发动机润滑系统可能不正常了。