英文文献 科技类 原文及翻译 （电子 电气 自动化 通信…） 1.docVIP

BALLAST CONTROL IC IR2156(S) Introduction The IR2156 incorporates a high voltage half-bridgegate driver with a programmable oscillator and state diagram to form a complete ballast control IC. The IR2156 features include programmable preheat and run frequencies, programmable preheat time, programmable dead-time, and programmable over-current protection. Comprehensive protection features such as protection from failure of a lamp to strike,filament failures, as well as an automatic restart function, have been included in the design. The IR2156 is available in both 14 lead PDIP and 14 lead SOIC packages. Figure 1 is a block diagram of its internal. Figure 1.1 Block diagram of the internal IR2156 IR2156 the main features are as follows: ? Ballast control and half-bridge driver in one IC ? Programmable preheat frequency, preheat time, over-current threshold, run frequency and dead time. ? DC bus under-voltage reset ? Shutdown pin with hysteresis ? Internal 15.6V zener clamp diode on on Vcc ? Micropower startup (150μA) ? Latch immunity and ESD protection Table 1.2 Recommended Operating Conditions Symbol Definition Min. Max. Units Vbs High side floating supply voltage VCC－0.7 Vclamp V Vs Steady state high side floating supply offset voltage －1 600 V VCC Supply voltage Vccuv＋ Vclamp V ICC Supply current 注2 10 mA CT CT lead capacitance 220 —— pF Isd Shutdown lead current －1 1 mA Ics Current sense lead current －1 1 mA Tj Junction temperature －40 125 ℃ Note 2: Enough current should be supplied into the VCC lead to keep the internal 15.6V zener clamp diode on this lead regulating its voltage, VCLAMP. Functional Description Under-voltage Lock-Out Mode (UVLO) The under-voltage lock-out mode (UVLO) is defined as the state the IC is in when VCC is below the turn-on threshold of the IC. To identify the different modes of the IC, refer to the State Diagram shown on page 6 of this document. The IR2156 undervoltage lock-out is designe