ONSEMI公司的NCV8876是一款非同步升壓控制器，用于汽車啟停使得輸入電池電壓驟降，輸出保持正常供電的應(yīng)用。該芯片采用內(nèi)部斜坡補償?shù)姆逯惦娏骺刂颇Ｊ?，控制外部N溝道MOSFET場效應(yīng)管。該芯片具有周期循環(huán)電流限制、熱關(guān)斷保護功能。本文首先介紹芯片的簡介、特性、內(nèi)部框圖及應(yīng)用領(lǐng)域，并給出相應(yīng)設(shè)計方案的設(shè)計原理圖、元器件列表及PCB元件布局圖。
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應(yīng)用：
• Applications Requiring Regulated Voltage through Cranking and Start−Stop Operation
圖1. NCV8876內(nèi)部方框圖
NCV8876方案介紹：
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方案原理圖：
圖2. NCV8876方案原理圖
NCV8876方案材料清單：
PCB元件布局圖：
