欢迎访问ic37.com |
会员登录 免费注册
发布采购

F72814 参数 Datasheet PDF下载

F72814图片预览
型号: F72814
PDF下载: 下载PDF文件 查看货源
内容描述: 同步降压PWM DC- DC控制器 [Synchronous Buck PWM DC-DC Controller]
分类和应用: 控制器
文件页数/大小: 16 页 / 487 K
品牌: FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
 浏览型号F72814的Datasheet PDF文件第4页浏览型号F72814的Datasheet PDF文件第5页浏览型号F72814的Datasheet PDF文件第6页浏览型号F72814的Datasheet PDF文件第7页浏览型号F72814的Datasheet PDF文件第9页浏览型号F72814的Datasheet PDF文件第10页浏览型号F72814的Datasheet PDF文件第11页浏览型号F72814的Datasheet PDF文件第12页  
F72814  
7. Function Description  
The F72814 is a single PWM DC-DC converter controller for application which requires high current such as motherboard,  
graphic card etc. The F72814 uses voltage mode PWM controller with fast transient response (driving two external N-channel  
MOSFETs in a synchronous rectified buck converter topology) and integrates some functions such as soft-start, over current and  
short circuit protections etc. Over current protection is achieved by monitoring the PHASE negative voltage when heavy loading  
without the need of a current sensing resistor and short circuit condition is detected through FB pin. If over current condition occurs,  
the F72814 will initiate the soft start cycle. After two cycles and the fault condition persist, the controller will go into shut down  
status. In shut down status, both gate drive signals will be low. To restart the controller, either recycling VCC supply or momentarily  
pulling the OCSET pin below 0.15V. If under voltage condition occurs, it will keep hiccup mode in this event.  
7.1 Bootstrap Operation  
In the single power supply system, UGATE is powered by an external bootstrap circuit as Figure 3. The Boot capacitor, CBOOT is  
charged and generated a floating reference voltage at PHASE pin. Typically, a 0.1uF CBOOT is enough for the most of applications.  
The CBOOT capacitor is refreshed and charged to a voltage of “VCC – Diode Drop” while low side power MOS turns on.  
5V to 12V  
3.3V/5V/12V  
BOOT  
VCC  
C
BOOT  
UGATE  
PHASE  
LGATE  
Q1  
Q2  
VOUT  
Fig 2. Power Supply Operation.  
7.2 Power On Reset  
The F72814S Power-on-reset monitors VCC supply voltage and input voltage at OCSET pin. POR level is 4.1V with 0.5V  
hysteresis at VCC voltage and 0.15V at OCSET voltage, The POR function initiates soft-start operation and resets control logic  
after the supply voltages exceeds its POR threshold voltage.  
F72814  
-5-  
V0.23P