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Drive control circuit of charged pump circuit

  • US 6,297,687 B1
  • Filed: 07/30/1999
  • Issued: 10/02/2001
  • Est. Priority Date: 08/11/1998
  • Status: Expired due to Fees
First Claim
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1. A drive control circuit for a charge pump circuit, the charge pump circuit includinga plurality of rectification elements connected in series between an input terminal and an output terminal, each of the rectification elements respectively including a node, and a plurality of capacitors each respectively having a first end and a second end, the first ends of the capacitors being coupled to respective ones of the nodes and clock signals being provided to the second ends of the capacitors, the charge pump circuit having a plurality of drive steps which raise a power source voltage that is supplied to the input terminal based on the clock signals, the clock signals including first and second clock signals which respectively change level, so that the clock signals provided to the capacitors coupled to the nodes of immediately adjacent ones of the rectification elements have high level periods that do not coincide, the drive control circuit comprising:

  • a power source voltage detecting circuit that detects the power source voltage at the input terminal;

    a control circuit that changes a number of drive steps of the charge pump circuit based on the detected power source voltage; and

    a by-pass circuit that selectively by-passes the drive steps of the charge pump circuit to provide a final output of the changed number of drive steps directly to the output terminal, in accordance with the change in the number of drive steps.

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