Switched-capacitor charge pumps, which offer a size advantage over the equivalent inductor-based regulator, are popular for boosting the battery voltage in small handheld equipment. As an example, the subscriber identification module (SIM) in European cellular phones requires a regulated 5V for powering low-current loads. One such circuit (Figure 1) employs two tiny SOT-23 ICs and three surface-mount capacitors to double and post-regulate the voltage of a single Li+ battery. It delivers 15mA from a 2.7V minimum output voltage. Figure 1. This 1-cell regulator circuit maintains a 5V output without the use of inductors. Battery voltage is boosted by a charge-pump voltage doubler with 2V–5.5V input range (IC1), and stepped down to the desired level by a micropower linear regulator (IC2). As the battery discharges, the system compensates declining voltage with an increase in efficiency, reaching 84% at 2.8V (Figure 2). Because the SIM and other smart cards are used only a few times a day and for less than a second each time, one can sacrifice some efficiency for smaller size and lower cost. The circuit's low quiescent current ranges from 60µA at 2.6V to 80µA at 3.6V. Figure 2. Efficiency for the Figure 2 circuit improves as the battery discharges. A similar version of this article appeared in the October 4, 1999 issue of EE Times magazine. 의견을 보내주세요! 위 내용이 도움이 되셨나요? 여러분의 의견을 기다립니다 — Maxim은 보내주신 정정이나 제안사항을 반영하고 있습니다. 이 페이지를 평가하고 의견을 보내주십시오. 자동 업데이트 관심있는 분야의 애플리케이션 노트가 나올 때 자동으로 업데이트 받고 싶으세요? 그렇다면 EE-Mail™을 신청하십시오. 추가 정보   APP 1791: Dec 03, 2002 MAX1615 노트북 컴퓨터용 고전압, 저전력 선형 레귤레이터 전체 데이터 시트 (PDF, 112kB) 무료 샘플 MAX1683 스위치드 커패시터 전압 더블러 전체 데이터 시트 (PDF, 200kB) 무료 샘플   다운로드, PDF 형식 (29kB)  AN1791, AN 1791, APP1791, Appnote1791, Appnote 1791