公开(公告)号：US20010011923A1

公开(公告)日：2001-08-09

申请号：US09826571

申请日：2001-04-05

Applicant: U.S. Philips Corporation

Inventor： Anthonius Bakker ,  Johan H. Huijsing

IPC: H03F001/02

CPC classification number: H03F1/303 ,  H03F3/387 ,  H03F3/45968 ,  H03F2200/81

Abstract: An amplifier (AMP) is provided with a pair of choppers (CHPi,CHPo) in order to reduce the DC-offset and the noise produced by the amplifier (AMP). To obtain an optimal noise reduction the pair of choppers (CHPi,CHPo) operate on a high frequency. As a result the DC-offset cancellation is not optimal because a so-called charge injection of the switches in the pair of choppers (CHPi,CHPo) produces a DC-offset. To overcome this problem the amplifier (AMP) is further provided with further offset cancellation means which are for example formed by a further pair of choppers (CHPfi,CHPfo). This further pair of choppers (CHPfi,CHPfo) operates on a relatively low frequency. The combination of the pair of choppers (CHPi,CHPo) and the further pair of choppers (CHPfi,CHPfo) guarantees an optimal DC-offset cancellation as well as an optimal noise cancellation.

Abstract translation: 放大器（AMP）具有一对斩波器（CHPi，CHPo），以减少DC偏移和放大器（AMP）产生的噪声。 为了获得最佳的噪声降低，该对斩波器（CHPi，CHPo）在高频下工作。 结果，直流偏移消除不是最佳的，因为所述一对斩波器（CHPi，CHPo）中的开关的所谓电荷注入产生DC偏移。 为了克服这个问题，放大器（AMP）还设置有另外的偏移消除装置，例如由另一对斩波器（CHPfi，CHPfo）形成。 这对另外的一对斩波器（CHPfi，CHPfo）在较低频率下工作。 一对斩波器（CHPi，CHPo）和另一对斩波器（CHPfi，CHPfo）的组合保证了最佳的DC偏移消除以及最佳的噪声消除。