ONSEMI公司的NCV8876是一款非同步升压控制器，用于汽车启停使得输入电池电压骤降，输出保持正常供电的应用。该芯片采用内部斜坡补偿的峰值电流控制模式，控制外部N沟道MOSFET场效应管。该芯片具有周期循环电流限制、热关断保护功能。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及PCB元件布局图。

The NCV8876 is a Non-Synchronous Boost controller designed to supply a minimum output voltage during Start-Stop vehicle operation battery voltage sags. The controller drives an external N-channel MOSFET. The device uses peak current mode control with internal slope compensation. The IC incorporates an internal regulator that supplies charge to the gate driver.

Protection features include, cycle-by-cycle current limiting, protection and thermal shutdown.

Additional features include low quiescent current sleep mode operation. The NCV8876 is enabled when the supply voltage drops below 7.3 V, with boost operation initiated when the supply voltage is below 6.8 V.

NCV8876主要特性：

• Automatic Enable Below 7.3 V (Factory Programmable)
• Boost Mode Operation at 6.8 V
• 2% Output Accuracy Over Temperature Range
• Peak Current Mode Control with Internal Slope Compensation
• Externally Adjustable Frequency Operation
• Wide Input Voltage Range of 2 V to 40 V, 45 V Load Dump
• Low Quiescent Current in Sleep Mode (<11 A Typical)
• Cycle−by−Cycle Current Limit Protection
• Hiccup−Mode Overcurrent Protection (OCP)
• Thermal Shutdown (TSD)
• This is a Pb−Free Device

NCV8876应用：

• Applications Requiring Regulated Voltage through Cranking and Start−Stop Operation

 
图1. NCV8876内部方框图

NCV8876方案介绍：

This NCV887601 evaluation board provides a convenient way to evaluate a high frequency boost controller designed to supply a minimum output voltage during Start-Stop vehicle battery voltage sags. The unit is in low Iq sleep-mode under normal battery operating condition and will wake-up when the monitored voltage drops below 7.3 V and begin regulating once 6.8 V is reached. Switching frequency is set to 440 kHz with a user selectable ROSC resistor. The evaluation board is rated 6.8 V / 3.6 A at a 2.6 V input voltage. Operation below 2.6 V is possible if output current is reduced.

Key Features

• Automatic enable below 7.3 V
• Boost Operation at 6.8 V
• 440 kHz Switching Frequency
• Input Undervoltage Lockout
• Wide Input Voltage of 2.6 V to 45 V
• Low Quiescent Current in Sleep Mode (<11 A Typical)
• Cycle-by-Cycle Current Limit Protection
• Status Monitoring
• Automotive Grade

NCV8876方案原理图：


图2. NCV8876方案原理图

NCV8876方案材料清单：



PCB元件布局图：