High voltage generator with oscillator servo-linked to low supply voltage
First Claim
1. A switch-over control circuit for a charge pump type of high voltage generator circuit having a set of capacitors and transistors, the switch-over control circuit charging the charge pump by selectively switching the connections between the capacitors and the transistors by issuing piloting signals, the switch-over circuit comprising:
- an oscillator for producing a clock signal;
piloting means for receiving the clock signal and producing the piloting signals; and
command means directing the oscillator to produce the clock signal at a frequency equal to a smallest frequency of a first frequency which is fixed and a second frequency which is dependent on the piloting signals.
1 Assignment
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Accused Products
Abstract
Disclosed is a high voltage generator circuit of the charge pump type. The rate of operation of this pump is set by a sequence of piloting signals produced out of a clock signal. This clock signal is itself produced by an oscillator. A frequency servo-link is set up between the clock signal produced by the oscillator and the running of the sequence in order to produce a clock signal with a frequency that is equal to the maximum permissible frequency for low supply voltages while at the same time limiting this frequency from a given supply voltage threshold onwards.
6 Citations
8 Claims
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1. A switch-over control circuit for a charge pump type of high voltage generator circuit having a set of capacitors and transistors, the switch-over control circuit charging the charge pump by selectively switching the connections between the capacitors and the transistors by issuing piloting signals, the switch-over circuit comprising:
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an oscillator for producing a clock signal; piloting means for receiving the clock signal and producing the piloting signals; and command means directing the oscillator to produce the clock signal at a frequency equal to a smallest frequency of a first frequency which is fixed and a second frequency which is dependent on the piloting signals. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for generating a clock signal for a charge pump type of high voltage generator circuit, comprising steps of:
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producing a clock signal; repetitively producing piloting signals out of the clock signal; and issuing a command signal to the oscillator to generate a clock signal at a frequency equal to a smallest frequency of a first fixed frequency and a second frequency dependent on the piloting signals. - View Dependent Claims (8)
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Specification