Differential amplifier, reference voltage generating circuit, differential amplifying method, and reference voltage generating method
AssigneeElpida Memory, Inc.
InventorAkira Ide
Life of this patent
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Abstract
A differential amplifier includes a main differential amplifier circuit that receives a pair of input signals and supplies a pair of output signals based on a difference between the input signals; and a bias control differential amplifier circuit that receives the pair of output signals, controls a control terminal of a current-limiting transistor making up the main differential amplifying circuit based on an offset voltage included in the output signals, and reduces the offset voltage.
Claims11
A differential amplifier comprising:
- a main differential amplifier circuit that receives a pair of input signals and supplies a pair of output signals based on a difference between the input signals, the main differential amplifier circuit including a current-limiting transistor;
- and
- a bias control differential amplifier circuit that receives the pair of output signals and controls a control terminal of the current-limiting transistor based on an offset voltage included in the output signals so as to reduce the offset voltage.
A differential amplifier comprising:
- a main differential amplifier circuit that includes a differential amplifier unit;
- and
- an open drain output circuit that amplifies a signal supplied from the main differential amplifier circuit,
- wherein when an offset voltage included in a differential output signal of the differential amplifier unit is detected, an operating point of the differential amplifier unit is controlled based on the offset voltage so as to reduce the offset voltage.
A differential amplifying method comprising:
- accepting input signals to a pair of complementary input terminals of a main differential amplifier circuit;
- obtaining a complementary signals by amplifying the input signals based on a control signal defining a bias current and supplied to a control terminal of the main differential amplifier circuit;
- outputting the complementary signals from a complementary pair of output terminals of the main differential amplifier circuit;
- supplying one of the complementary signals to a MOS transistor;
- outputting a signal from a drain of a MOS transistor;
- obtaining the control signal by differential amplifying the first complementary signals;
- and
- supplying the control signal to the control terminal.
A reference voltage generating method by a reference voltage generating circuit including a bandgap power supply and a differential amplifier unit, the differential amplifier unit including a main differential amplifier circuit performing overall differential amplification and a open drain output circuit amplifying a differential output signal supplied from the main differential amplifier circuit, the differential amplifier unit outputs a signal amplified by the open drain output circuit,
- the reference voltage generating method comprising:
- supplying signals outputted from the bandgap power supply to the main differential amplifier circuit;
- detecting an offset voltage included in a differential output signal outputted from the differential amplifier unit as the differential amplifier unit accepts the signals outputted from the bandgap power supply;
- and
- reducing the offset voltage included in the differential output signals by controlling an operating point of the main differential amplifier unit based on the offset voltage.
Dependencies are inferred from the claim text.