Renesas EZ－0011 8位MCU LED照明控制方案

Renesas公司的78K0/Ix2 8 位单片微控制器系列包括78K0/IY2, 78K0/IA2和78K0/IB2,采用78K0 CPU 内核,高速时钟可达10MHz, 电源电压 VDD = 2.7 至5.5 V,VDD为5V时的工作模式电流为350 μA, STOP模式的电流为0.58 μA,主要用于LED照明控制.本文介绍了78K0/Ix2 8 位单片微控制器主要特性,方框图,以及78K0/IB2 PFC LED照明评估板主要特性, LED照明系统框图,电路图和相应的材料清单.

78K0/Ix2 8 位单片微控制器主要特性:

56443 . 78K0 CPU 内核

56443 . I/O 端口，ROM 和RAM 容量



低功耗 (VDD = 5.0 V)

• 内部高速振荡工作模式: 350 μA (TYP.) (工作在fCPU = 1 MHz )

• STOP 模式: 0.58 μA (TYP.) (工作在fIL = 30 kHz )

Clock

• 高速系统时钟 … 可从以下四种时钟源中选择

- 陶瓷/晶体振荡器： 1 至 10 MHz

- 外部时钟： 1 至 10 MHz 注

- 内部高速振荡器： 4 MHz ± 2 % （–20 至 +70℃）注，或8 MHz ± 5 %（–40 至 +85℃）

- 16 位定时器X0 和X1 的时钟： 40 MHz （典型值） （使用 PLL 时）

• 内部低速振荡器 30 kHz ± 10 % … 看门狗定时器，间歇操作中的定时器时钟

定时器

• 16 位定时器X … PWM 输出（40 MHz （MAX.） 时钟工作），与外部信号联动操作，多达四个通道的同步输出，触发A/D 转换

• 16 位定时器/事件计数器 … PPG 输出，捕获输入，外部事件计数器输入

• 8 位定时器H1 … PWM 输出，可工作于内部低速振荡时钟

• 8 位定时器/事件计数器 51 … 外部事件计数器输入

• 看门狗定时器 … 可在内部低速振荡时钟下工作



串行接口

• UART6 … 异步2-线串行接口

• DALI … 用于照明控制（从模式）的2-线串行接口

• IICA … 时钟同步2-线串行接口，支持多主机通信

从模式下可通过地址匹配释放待机模式

• CSI11 … 时钟同步3-线串行接口，从模式下可作为SPI 操作



乘法器 （8 位× 8 位 = 16 位， 16 位× 16 位 = 32 位， 1 个时钟工作）

10 位分辨率的A/D 转换

• 78K0/IY2： 5 通道

• 78K0/IA2： 6 通道

• 78K0/IB2： 9 通道

运算放大器 （仅限于内置运算放大器的产品）： 1 通道

比较器： 3 通道

上电清零电路（POC）

低电压检测电路（LVI） （当达到检测电压时产生中断/复位（可选择））

• 检测电压： 可从 2.84 和4.22 V 间的十个等级中选择在设置 LVI 默认开始后，仅当开启电源时使用1.91 V。

单电源 flash 存储器

• 允许 Flash 自编程

• 软件保护功能：防止外部拷贝（没有 flash 读取命令）

安全功能

• 看门狗定时器使用独立于 CPU 的时钟工作即使系统时钟停止时也可检测到异常

• 用 LVI 可检测供应电压下降在供应电压下降到低于工作电压前进行适当的处理

• 具有选项字节功能重要的系统操作在硬件中设置

片上调试功能 …用于目标器件的控制，以及引用内存

支持汇编语言和 C 语言

提升开发环境（开发中）

• 支持全功能仿真器（IECUBE）， 和简易仿真器（MINICUBE2）

电源供应电压： VDD = 2.7 至5.5 V

运行环境温度： TA = –40 至 +105℃

图1.78K0/IY2方框图

图2.78K0/IA2方框图

图3.78K0/IB2方框图

78K0/IB2 PFC LED照明评估板

78K0/IB2 PFC LED Lighting Evaluation Board

Lighting accounts for about 16% of domestic household power consumption

The use of LED’s in lighting has been increasingly popular in recent years due to the reduction of CO2 emissions and the needs for energy saving. This is because LED lighting has higher luminance efficiency and a longer life than the conventional incandescent bulbs or fluorescent lights. For energy saving in systems, there are greater
needs for optimal ON/OFF control and dimming control for lighting using communication and sensors, and lighting system control with microcontrollers is required. On the other hand, there are greater needs for low costs for promoting LED lighting. There have been many cases in which board platforms are used to reduce development man-hours or the functions of analog control IC’s are built into a microcontroller.

With these needs, this application note describes the features, system configuration, and control methods of LED lighting system with the 78K0/Ix2 microcontroller by using the LED lighting evaluation board with PFC control EZ-0011 (Photo 1-1) as an example. To purchase the EZ-0011, contact Renesas Electronics sales office or Distributor.

78K0/Ix2 LED照明控制系统主要特性:

Features of LED Lighting System Control with 78K0/Ix2

The LED lighting system with the 78K0/Ix2 microcontroller has the following features:

Allows LED constant current/dimming control of up to 6 channels with the timer output function of the 16-bit timers X0, X1, 00 and 8-bit timer H1. This eliminates the need for an IC for LED constant current control, reducing the cost of the set.

Allows power factor correction (PFC) control with the timer restart function that works with the comparator of the 16-bit timer X0. This eliminates the need for an IC for PFC control, reducing the cost of the set.

Realizes the protective function that causes emergency stop of PWM output immediately (without the CPU) in case of a detection of overcurrent or overvoltage in the LED or PFC control part by using the high impedance output function that works with the comparator of the 16-bit timers X0 and X1. This eliminates the need for a dedicated protective circuit with an external comparator, reducing the cost of the set.

Furthermore, operation after the emergency stop can be controlled by software, realizing a flexible protective function according to the system.

Realizes transmission and reception of Manchester codes (transmission: 11 bits, reception: 19 bits) in compliance with the DALI communication standard with built-in hardware by using the DALI communication slave function of the serial interface UART6/DALI. This can reduce CPU load during data transmission and reception.

The reception pin RxD6 of the serial interface UART6/DALI can be connected to the external interrupt pin INTP0 and the capture input pin TI000 of the 16-bit timer 00 inside the microcontroller. This realizes stand-by mode cancellation during the break period reception (low level for 88 μs to 1 s) of DMX512 communication as well as pulse width measurement during the break period.

Realizes pulse width measurement during infrared remote control signal reception Note with hardware by using the pulse width measurement function of the 16-bit timer 00. This can reduce CPU load during data reception.

Flexibly realizes time management and control during sensor detection Note with software processing of the Microcontroller.

图4.采用78K0/Ix2 MCU的LED照明系统框图

图5.用于LED恒流控制的反激转换器l
Example of Fly-back Converter Type PFC Circuit Configuration with 78K0/Ix2 Microcontroller

图6.采用78K0/Ix2 MCU的LED照明系统外形图

图7.采用78K0/Ix2 MCU的LED照明系统电路图
采用78K0/Ix2 MCU的LED照明系统材料清单:



详情请见:
http://www2.renesas.com/maps_download/pdf/U19353CA3V0UD00.pdf
和
http://www2.renesas.com/micro/en/solution/data/EZ-PFCLED-002_Schematic.pdf
以及
http://www2.renesas.com/micro/en/solution/data/ZBB-CB-11-0021-E.pdf
和
http://www2.renesas.com/maps_download/pdf/R01AN0674EJ0100_78K0IX2.pdf