HoltekHT7A4016非隔离式DC电源解决方案

LED TV的LED背光照明.本文介绍了HT7A4016主要特性,方框图以及针对各种不同应用电路的参考设计电路.

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应用:

• Switching AC-DC Adaptors

• DC-DC Switching Buck/Boost Converters

• LED Backlights for LCD/LED TVs

图1. HT7A4016方框图

图2. HT7A4016典型应用电路图

图3. HT7A4016恒压升压应用电路图(DC/DC升压)

图4. HT7A4016用于背光LED驱动的DC/DC恒流升压应用电路图

图5. HT7A4016 LED照明驱动的恒流降压应用电路图

图6. HT7A4016恒流降压稳压器应用电路图(高边降压)

图7. HT7A4016初级反馈的隔离反激AC/DC转换器电路图
详情请见:
http://www.holtek.com.tw/PDF/Power_Management/ht7a4016v100.pdf