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Holtek公司的HT7A4016是低功耗寬溫度范圍的通用電流模式PWM控制器,滿足能量之星2.0規(guī)范,起動(dòng)電流低于20uA和很低工作電流,ESD保護(hù)大于3kV,調(diào)整振蕩器精度±5%,內(nèi)部具有斜率補(bǔ)償,主要用在開(kāi)關(guān)電源AC/DC適配器,DC/DC降壓/升壓轉(zhuǎn)換器,LCD/LED TV的LED背光照明.本文介紹了HT7A4016主要特性,方框圖以及針對(duì)各種不同應(yīng)用電路的參考設(shè)計(jì)電路. The HT7A4016 is a controller IC that includes the necessary features to implement off-line or DC-DC current mode control schemes with a minimal external parts count. Internal circuits include a specially designed Mixed-Mode/Analog Interface for multi-function and multi-topology control schemes (DC-DC Buck/Boost, Off-line AC-DC), a trimmed oscillator for precise duty-cycle control under voltage lockout with a start-up current of less than 0.5mA, a wide temperature range, precise voltage reference, internal Slope Compensation and Leading-Edge Blanking. The HT7A4016 features basic system protection functions such as Cycle-by-Cycle Current Limiting and Under Voltage Lock-Out (UVLO). A Multi-Function Pin can be used as a dimming function for LED driving, and as a primary feedback control f o r Primary - Side Feed back AC - DC applications. HT7A4016主要特性: • High Performance, Low Cost Current Mode PWM Controller especially designed for Energy Star 2.0 • Very Low Startup Current (<20μA) and Operating Current • High-Voltage CMOS Process with Excellent ESD protection (>3KV) • ±5% Trimmed Oscillator for Precise Frequency Control • LEB (Leading-Edge Blanking) on CS Pin • Internal Slope Compensation • Programmable Switching Frequency • Internally Trimmed Reference with UVLO (Under Voltage Lockout) • Cycle-by-Cycle Current Limiting HT7A4016應(yīng)用: • Switching AC-DC Adaptors • DC-DC Switching Buck/Boost Converters • LED Backlights for LCD/LED TVs 
圖1. HT7A4016方框圖
圖2. HT7A4016典型應(yīng)用電路圖
圖3. HT7A4016恒壓升壓應(yīng)用電路圖(DC/DC升壓)
圖4. HT7A4016用于背光LED驅(qū)動(dòng)的DC/DC恒流升壓應(yīng)用電路圖
圖5. HT7A4016 LED照明驅(qū)動(dòng)的恒流降壓應(yīng)用電路圖
圖6. HT7A4016恒流降壓穩(wěn)壓器應(yīng)用電路圖(高邊降壓)
圖7. HT7A4016初級(jí)反饋的隔離反激AC/DC轉(zhuǎn)換器電路圖 詳情請(qǐng)見(jiàn): 
ht7a4016v100[1].pdf
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