Level Shifting Digital Signals
level shifting digital signals
by:budge ing
abstract:with only a single-polarity power supply, digital systems often have a problem translating an opposite-polarity pulse train into a positive or negative pulse output. this application note presents three simple circuits that can level shift the digital signals easily and reliably. the max913 comparator is featured in the designs.
this design idea appeared in the june 22, 2006 issue of electronic design magazine.
for positive-supply systems, the circuit of figure 1 transforms a negative pulse train into positive output pulses. the comparator shown (max913) provides both in-phase and out-of-phase outputs. (if the system requires only one output phase, you can choose an alternative single-output comparator.) voltage at the inverting input swings between 1.8v and 3.0v; r1 = r2 sets the noninverting input voltage to 2.5v. outputs for the comparator shown then provide positive pulse trains.
figure 1. operating on a positive supply, this circuit accepts negative input pulses and produces complementary bipolar outputs.
for negative-supply systems, the circuit of figure 2 transforms a positive pulse train into negative output pulses. voltage at the inverting input swings between -1.8v and -3v; r1 = r2 sets the noninverting input voltage to -2.5v. the complementary comparator outputs provide negative pulse trains.
figure 2. operating on a negative supply, this circuit accepts positive input pulses and produces complementary bipolar outputs.
figures 3 and 4 use the comparator as a buffer, thereby providing an interface for systems in which the input signal and the system supply voltage have opposite polarities. the figure 3 circuit enables a system with a positive supply voltage to accept negative pulses. in figure 4, the input signal is positive and the system supply is negative. both circuits use an npn transistor to level shift the comparator's outputs by vbe (r5 + r4)/r5 ≈ 4.5v. (for single-phase outputs, you can choose an alternative single-output comparator.)
figure 3. this circuit translates negative output to positive output pulses. it operates with a negative comparator supply and a positive system supply.
figure 4. this circuit translates positive output to negative output pulses. it operates with a positive comparator supply and a negative system supply.
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by:budge ing
abstract:with only a single-polarity power supply, digital systems often have a problem translating an opposite-polarity pulse train into a positive or negative pulse output. this application note presents three simple circuits that can level shift the digital signals easily and reliably. the max913 comparator is featured in the designs.
this design idea appeared in the june 22, 2006 issue of electronic design magazine.
for positive-supply systems, the circuit of figure 1 transforms a negative pulse train into positive output pulses. the comparator shown (max913) provides both in-phase and out-of-phase outputs. (if the system requires only one output phase, you can choose an alternative single-output comparator.) voltage at the inverting input swings between 1.8v and 3.0v; r1 = r2 sets the noninverting input voltage to 2.5v. outputs for the comparator shown then provide positive pulse trains.
figure 1. operating on a positive supply, this circuit accepts negative input pulses and produces complementary bipolar outputs.
for negative-supply systems, the circuit of figure 2 transforms a positive pulse train into negative output pulses. voltage at the inverting input swings between -1.8v and -3v; r1 = r2 sets the noninverting input voltage to -2.5v. the complementary comparator outputs provide negative pulse trains.
figure 2. operating on a negative supply, this circuit accepts positive input pulses and produces complementary bipolar outputs.
figures 3 and 4 use the comparator as a buffer, thereby providing an interface for systems in which the input signal and the system supply voltage have opposite polarities. the figure 3 circuit enables a system with a positive supply voltage to accept negative pulses. in figure 4, the input signal is positive and the system supply is negative. both circuits use an npn transistor to level shift the comparator's outputs by vbe (r5 + r4)/r5 ≈ 4.5v. (for single-phase outputs, you can choose an alternative single-output comparator.)
figure 3. this circuit translates negative output to positive output pulses. it operates with a negative comparator supply and a positive system supply.
figure 4. this circuit translates positive output to negative output pulses. it operates with a positive comparator supply and a negative system supply.
飞思卡尔半导体公司推出新的微机电系统加速计 用于智能电表应用的物理篡改防护
半导体光敏元件基础知识
服务机器人革新家居生活 普及仍需时间
改善汽车中的卫星导航系统的新方法详细剖析
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Level Shifting Digital Signals
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TerrePower将在北美底特律车展上重点展示电动汽车电池技术
旧电脑升级aigo国民好物NVMe固态硬盘，再战几年不是问题
数据存储和AI正在推动着自动驾驶技术的发展
什么是半导体？功率半导体器件的分类 功率MOS器件结构及工作原理
哪些先进封装技术成为“香饽饽”
视频编码器的作用以及视频编码器能应用的场合
中国信息通信安全所长魏亮表示网络架构变化将给5G安全带来五大风险
苹果明年将发布5款新iPhone 支持5G是明年下半年的最重要技术
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