Renesas公司的78K0/Ix2 8 位單片微控制器系列包括78K0/IY2, 78K0/IA2和78K0/IB2,采用78K0 CPU 內核,高速時鐘可達10MHz, 電源電壓 VDD = 2.7 至5.5 V,VDD為5V時的工作模式電流為350 μA, STOP模式的電流為0.58 μA,主要用于LED照明控制.本文介紹了78K0/Ix2 8 位單片微控制器主要特性,方框圖,以及78K0/IB2 PFC LED照明評估板主要特性, LED照明系統框圖,電路圖和相應的材料清單.

78K0/Ix2 8 位單片微控制器主要特性:

56443 . 78K0 CPU 內核

56443 . I/O 端口，ROM 和RAM 容量



低功耗 (VDD = 5.0 V)

• 內部高速振蕩工作模式: 350 μA (TYP.) (工作在fCPU = 1 MHz )

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

Clock

• 高速系統時鐘 … 可從以下四種時鐘源中選擇

- 陶瓷/晶體振蕩器： 1 至 10 MHz

- 外部時鐘： 1 至 10 MHz 注

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

- 16 位定時器X0 和X1 的時鐘： 40 MHz （典型值） （使用 PLL 時）

• 內部低速振蕩器 30 kHz ± 10 % … 看門狗定時器，間歇操作中的定時器時鐘

定時器

• 16 位定時器X … PWM 輸出（40 MHz （MAX.） 時鐘工作），與外部信號聯動操作，多達四個通道的同步輸出，觸發A/D 轉換

• 16 位定時器/事件計數器 … PPG 輸出，捕獲輸入，外部事件計數器輸入

• 8 位定時器H1 … PWM 輸出，可工作于內部低速振蕩時鐘

• 8 位定時器/事件計數器 51 … 外部事件計數器輸入

• 看門狗定時器 … 可在內部低速振蕩時鐘下工作



串行接口

• UART6 … 異步2-線串行接口

• DALI … 用于照明控制（從模式）的2-線串行接口

• IICA … 時鐘同步2-線串行接口，支持多主機通信

從模式下可通過地址匹配釋放待機模式

• CSI11 … 時鐘同步3-線串行接口，從模式下可作為SPI 操作



乘法器 （8 位× 8 位 = 16 位， 16 位× 16 位 = 32 位， 1 個時鐘工作）

10 位分辨率的A/D 轉換

• 78K0/IY2： 5 通道

• 78K0/IA2： 6 通道

• 78K0/IB2： 9 通道

運算放大器 （僅限于內置運算放大器的產品）： 1 通道

比較器： 3 通道

上電清零電路（POC）

低電壓檢測電路（LVI） （當達到檢測電壓時產生中斷/復位（可選擇））

• 檢測電壓： 可從 2.84 和4.22 V 間的十個等級中選擇在設置 LVI 默認開始后，僅當開啟電源時使用1.91 V。

單電源 flash 存儲器

• 允許 Flash 自編程

• 軟件保護功能：防止外部拷貝（沒有 flash 讀取命令）

安全功能

• 看門狗定時器使用獨立于 CPU 的時鐘工作即使系統時鐘停止時也可檢測到異常

• 用 LVI 可檢測供應電壓下降在供應電壓下降到低于工作電壓前進行適當的處理

• 具有選項字節功能重要的系統操作在硬件中設置

片上調試功能 …用于目標器件的控制，以及引用內存

支持匯編語言和 C 語言

提升開發環境（開發中）

• 支持全功能仿真器（IECUBE）， 和簡易仿真器（MINICUBE2）

電源供應電壓： VDD = 2.7 至5.5 V

運行環境溫度： TA = –40 至 +105℃

圖1.78K0/IY2方框圖

圖2.78K0/IA2方框圖

圖3.78K0/IB2方框圖

78K0/IB2 PFC LED照明評估板

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照明控制系統主要特性:

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.

圖4.采用78K0/Ix2 MCU的LED照明系統框圖

圖5.用于LED恒流控制的反激轉換器l
Example of Fly-back Converter Type PFC Circuit Configuration with 78K0/Ix2 Microcontroller

圖6.采用78K0/Ix2 MCU的LED照明系統外形圖

圖7.采用78K0/Ix2 MCU的LED照明系統電路圖
采用78K0/Ix2 MCU的LED照明系統材料清單:



詳情請見:
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