调节液晶偏压发生器无需电感器-Regulated LCD-B
a stringent height limitation on the pc boards for personal digital assistants (pdas) and palmtop computers compels the use of expensive, low-profile inductors in switch-mode power supplies. as an alternative, however, certain switch-mode circuits can be replaced with one based on a charge pump (figure 1). this example generates a regulated negative voltage suitable for biasing an lcd.
figure 1. adding a few inexpensive components in the feedback path of ic1 enables the generation of regulated output voltages nearly as high as -4vin.
ic1 contains a regulated, inverting charge pump that produces output voltages as high as -2vin, in which the supply voltage (vin) can range from +1.8v to +5.5v. the ic regulates vout through pulse-frequency modulation (pfm), with a maximum frequency of 450khz. the ic's low quiescent current (30µa) provides excellent light-load efficiency without sacrificing full-load capability.
inserting an external, discrete charge pump (consisting of c3, c4, and the schottky diodes) in the feedback path of ic1 produces an inverter-quadrupler circuit whose regulated output level is set by the ratio of feedback resistors r1 and r2:
vout = -vin (r1/r2)
configured as shown, the circuit provides up to 15ma at vout = -18v, with 76% efficiency and 60mv of output voltage ripple. lower vout allows higher output currents: vout = -15v yields 20ma, and vout = -12v yields 30ma.
a similar idea appeared in the 3/9/98 issue of electronic design.
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figure 1. adding a few inexpensive components in the feedback path of ic1 enables the generation of regulated output voltages nearly as high as -4vin.
ic1 contains a regulated, inverting charge pump that produces output voltages as high as -2vin, in which the supply voltage (vin) can range from +1.8v to +5.5v. the ic regulates vout through pulse-frequency modulation (pfm), with a maximum frequency of 450khz. the ic's low quiescent current (30µa) provides excellent light-load efficiency without sacrificing full-load capability.
inserting an external, discrete charge pump (consisting of c3, c4, and the schottky diodes) in the feedback path of ic1 produces an inverter-quadrupler circuit whose regulated output level is set by the ratio of feedback resistors r1 and r2:
vout = -vin (r1/r2)
configured as shown, the circuit provides up to 15ma at vout = -18v, with 76% efficiency and 60mv of output voltage ripple. lower vout allows higher output currents: vout = -15v yields 20ma, and vout = -12v yields 30ma.
a similar idea appeared in the 3/9/98 issue of electronic design.
阿尔法：数字货币量化投资的优势在哪里？如何操作
自己编写函数示例代码很难吗？分享几个示例！
铠侠发布新款PM6系列固态硬盘，目前容量最大的2.5寸固态硬盘
PCB为什么发生甩铜？这3个原因给说全了
示波器如何捕捉瞬间波形，让信号无所遁形！
调节液晶偏压发生器无需电感器-Regulated LCD-B
深度剖析电子级玻纤布行业市场
中国互联网巨头入场芯片领域
金砖国家需求旺盛 中国安防企业淘金正当时
中国联通携手华为成功完成了5G+4K超高清视频直播场景下的验证
8阶连续时间滤波器芯片MAX274的工作原理及应用设计
模块化照明改变人类对照明的固有概念，全新的模块化照明时代来临
分析宽带系统互联中的串行选择
新疆哈密燃机发电项目正式并网发电，利用园区内煤化工废弃尾气发电
ARM携手英特尔消除物联网扩展障碍
沟槽结构SiC MOSFET常见的类型
关于全息投影和人工智能的分析
FPGA的应用领域
片上软件需要什么安全完整性？
发现了苹果iOS11的控制中心的不同之处了吗？你还有不满的吗？