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:
http://www.holtek.com.tw/PDF/Power_Management/ht7a4016v100.pdf