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US 4,902,959 AGranted
Band-gap voltage reference with independently trimmable TC and output
AssigneeAnalog Devices, Inc.
InventorAdrian P. Brokaw
Life of this patent
Estimating the term…
Abstract
An IC band-gap voltage reference including a pair of transistors having different emitter areas and driven by an amplifier feedback circuit to produce equal collector currents so as to develop an output voltage corresponding to the band-gap voltage. The amplifier output network includes a resistor network arranged to produce an output voltage which is a predetermined multiple of the band-gap voltage. The circuit provides for independent trimming of elements for adjusting the output voltage magnitude and its temperature coefficient.
Claims20
An IC band-gap voltage reference comprising:
- a pair of transistors each having base, collector and emitter electrodes;
- said emitter electrodes being connected together;
- amplifier means coupled to said pair of transistors to produce an output signal responsive to the difference between the currents through said pair of transistors;
- a feedback circuit coupled to said amplifier means and developing a feedback signal corresponding to said output signal;
- a current mirror forming part of said feedback circuit and coupled to said pair of transistors to force the combined current through said transistor pair to track said feedback signal;
- means to establish different current densities in the separate transistors of said pair of transistors;
- an output circuit for said amplifier means and having an output terminal for developing a DC output voltage;
- a network comprising resistor means and connected to said output circuit to carry a current corresponding to said output voltage;
- means connecting the voltage across at least a part of said resistor means as a differential signal to said bases of said pair of transistors respectively to drive the current through said transistors to an equilibrium condition with the voltage between said transistor bases corresponding to the .DELTA.V.sub.BE voltage of said two transistors;
- and
- a transistor diode forming part of said network to provide that said output voltage is responsive to the combination of said .DELTA.V.sub.BE voltage and the V.sub.BE voltage of said diode, said output voltage thereby serving as a temperature-compensated reference voltage.
8 more elements
An IC band-gap voltage reference comprising:
- a pair of transistors each having base, collector and emitter electrodes;
- said emitter electrodes being connected together;
- amplifier means having its input coupled to said pair of transistors to produce an output responsive to the difference between the currents through said pair of transistors;
- means to produce different current densities in said pair of transistors;
- an output circuit for said amplifier means and including an output terminal to develop an output voltage;
- a first resistor string connected at one end to said output circuit to carry a current corresponding to said output voltage;
- negative feedback means connecting the voltage across at least a part of said first resistor string as a differential signal to the bases of said pair of transistors respectively, to tend to drive said transistors toward equilibrium condition with the voltage between said bases corresponding to the .DELTA.V.sub.BE voltage of said transistors;
- a diode connected with said first resistor string such that the diode V.sub.BE is in series with said .DELTA.V.sub.BE voltage;
- a second resistor string connected a one end to said output circuit;
- and
- means connecting a common node of said second resistor string to the end of said first resistor string which is remote from said one end, thereby to develop at said output terminal a temperature-compensated voltage which is a predetermined multiple of the band-gap voltage.
8 more elements
An IC band-gap voltage reference comprising:
- a pair of transistors each having base, collector and emitter electrodes;
- amplifier means having its input coupled to said pair of transistors to produce an output responsive to the difference between the currents through said pair of transistors;
- means to produce different current densities in said pair of transistors;
- an output circuit for said amplifier means and including an output terminal to develop an output voltage;
- a first string of at least two resistors connected at one end to said output circuit to carry a current corresponding to said output voltage;
- a diode connected to the other end of said resistor string and developing a V.sub.BE voltage in series with the voltage across said first string resistors;
- negative feedback means connecting the voltage across at least a part of said first resistor string as a differential signal to the bases of said pair of transistors respectively, to tend to drive said transistors towards an equilibrium condition with the voltage across said part of said resistor string corresponding to the .DELTA.V.sub.BE voltage of said pair of transistors and in series with said diode V.sub.BE ;
- and
- a resistor network connected to said output circuit and to said diode to develop at said output terminal a temperature-compensated reference voltage which is a multiple of the band-gap voltage.
6 more elements
Dependencies are inferred from the claim text.