US 5,699,018 A · Negative voltage generator

Abstract

An output voltage of a negative voltage generator contains a ripple because of a ripple occurring in a voltage produced by a charge pump circuit in the negative voltage generator. When the negative voltage is supplied to an FET amplifier, there arises a possibility that an unwanted spurious component occurs in an output of the FET amplifier. Since each of pair of circuits, that generate a negative voltage, are made mutually complementary, two charge pump circuits are used to cancel ripples. A ripple appearing in an output voltage can therefore be suppressed, and a negative voltage can eventually be supplied more stably. When the negative voltage generator is connected to, for example, an FET amplifier in order to supply a gate bias voltage to each FET in the FET amplifier, an unwanted spurious component that may be contained in an output of the FET amplifier can be removed.

Claims12

Dependent claims

A negative voltage generator comprising:

oscillating signal means for providing an oscillating signal and a complementary oscillating signal;
negative voltage generating means including a pair of drive circuits for amplifying the oscillating signal and the complementary oscillating signal, respectively, and a pair of charge pump circuits that reverse polarities of outputs of said pair of drive circuits, the charge pump circuits having respective output terminals that are connected together, said negative voltage generating means combining signals produced by reversing the polarities of the oscillating and complementary oscillating signals, thus generating a negative voltage;
and
level control means for converting the level of the negative voltage and supplying a resultant voltage as an output voltage.

1 more element

A negative voltage generator comprising:

oscillating signal means for providing an oscillating signal and a complementary oscillating signal;
negative voltage generating means for amplifying the oscillating signal and the complementary oscillating signal, and for combining signals produced by reversing the polarities of the oscillating and complementary oscillating signals, thus generating a negative voltage;
and
level control means for converting the level of the negative voltage and supplying a resultant voltage as an output voltage, said level control means including a source follower transistor circuit for determining the output voltage using the negative voltage as a common level, said source follower transistor circuit having either a resistive load or a constant-current load to minimize variation of the output voltage induced by an output current, and including a current mirror circuit for stabilizing a gate voltage of said source follower transistor circuit.

1 more element

A negative voltage generator, comprising:

oscillating signal means for providing an oscillating signal;
negative voltage generating means for amplifying the oscillating signal, for reversing polarity of the oscillating signal, and for generating a negative voltage;
and
level control means for converting the level of the negative voltage and supplying a resultant voltage as an output voltage wherein said level control means includes a source follower transistor circuit for determining an output voltage using the negative voltage as a common level, said source follower transistor circuit having either a resistive load or a constant-current load to minimize variation of the output voltage induced by an output current, and said source follower transistor circuit includes a current mirror circuit for stabilizing a gate voltage of said source follower transistor circuit.

1 more element

Dependencies are inferred from the claim text.

Negative voltage generator

Life of this patent

Negative voltage generator

Life of this patent

Abstract

Claims12