A Novel Low-Power Dissipation and High-Speed Converter-Control-IC for the Transmitting Amplifier of Digital Portable Telephones

Nobuhiko YAMASHITA  Takuji SERADA  Tatsuo SAKAI  Kazuo TSUKAMOTO  Toshiaki YACHI  

IEICE TRANSACTIONS on Communications   Vol.E77-B   No.12   pp.1600-1606
Publication Date: 1994/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Power Supply
portable telephone,  switching DC amplifier,  power IC,  BiCMOS,  converter,  

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A novel low-power dissipation and high-speed converter-control-IC has been developed for the transmitting amplifier in digital portable telephones. The IC consists mainly of CMOS devices to reduce the bias current. To improve circuit speed, bipolar transistors are used in the output stage of the operational amplifier and in the current sources of the oscillator because they have a larger current capability and smaller parasitic capacitance than CMOS devices. The IC has one-fifth the bias current of a conventional control circuit consisting of discrete devices, and it can operate up to a switching frequency of 3MHz. The small bias current increases converter efficiency, and the high switching frequency reduces converter size. Using this IC, converter loss is 17% less than that with a conventional control circuit.