×

Method and apparatus for regulated low voltage charge pump

  • US 5,694,308 A
  • Filed: 07/03/1995
  • Issued: 12/02/1997
  • Est. Priority Date: 07/03/1995
  • Status: Expired due to Term
First Claim
Patent Images

1. A low voltage charge pump comprising:

  • start-up clock circuit that produces a clock signal having a first clock phase and a second clock phase, and the start-up clock circuit operates from a supply voltage having a voltage difference of less than 2.6 volts between a voltage source and a common reference, wherein during a startup period the clock signal is produced without the presence of an external clock;

    an output capacitor having a first terminal coupled to a reference voltage terminal, and a second terminal for providing an output voltage;

    capacitance charge circuit comprising;

    a current limiting device operably coupled to receive the clock signal, a first charge signal, a current limiting input signal, and to provide a second charge signal, wherein the current limiting device controls a rate of change of the second charge signal based on the current limiting input signal and the first charge signal;

    a charge circuit capacitor operably coupled to receive the second charge signal from the current limiting device, and to the second terminal of the output capacitor, wherein during the first clock phase the charge circuit capacitor is charged based on the second charge signal, and during the second clock phase the charge circuit capacitance is being discharged into the output capacitor to produce an output voltage; and

    regulation circuit operably coupled to receive the output voltage, and to provide the first charge signal, wherein the regulation circuit controls a maximum value of the first charge signal such that the output voltage is regulated.

View all claims
  • 18 Assignments
Timeline View
Assignment View
    ×
    ×