Electricity: power supply or regulation systems – Self-regulating – Using a three or more terminal semiconductive device as the...
Reexamination Certificate
1999-03-04
2001-01-30
Wong, Peter S. (Department: 2838)
Electricity: power supply or regulation systems
Self-regulating
Using a three or more terminal semiconductive device as the...
C323S314000, C323S907000
Reexamination Certificate
active
06181121
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to bandgap reference circuits generally and, more particularly, to a bandgap reference circuit that may operate at low supply voltages and may use a BiCMOS process.
BACKGROUND OF THE INVENTION
Conventional bandgap reference circuits generally develop a constant reference voltage and may use an operational amplifier to cause currents to be equal or to cause certain voltages to be equal. Additionally, conventional bandgap reference circuits may generate a bandgap voltage and then translate the bandgap voltage into a current.
FIG. 1
illustrates one conventional bandgap voltage circuit. An operational amplifier
12
generally forces its inputs to be equal. However, the implementation of the operational amplifier
12
generally limits headroom. The operational amplifier
12
generally requires extra circuitry to maintain stability in the feedback loops.
FIG. 1
is generally limited to generating a current that is proportional to absolute temperature (PTAT).
FIG. 2
illustrates a conventional bandgap circuit that can be found in U.S. Pat. No. 4,849,684. The circuit of
FIG. 2
is generally limited to generating a current that is proportional to absolute temperature.
FIG. 3
illustrates a conventional bandgap circuit that can be found in U.S. Pat. No. 5,559,425. The circuit of
FIG. 3
, similar to the circuits of
FIGS. 1 and 2
, is generally limited to generating a current that is proportional to absolute temperature.
FIG. 4
illustrates a bandgap circuit that can be found in U.S. Pat. No. 4,935,690. The circuit of
FIG. 4
is generally limited to presenting either a voltage output, or a current that is proportional to absolute temperature.
FIG. 5
illustrates a bandgap circuit that can be found in U.S. Pat. No. 4,450,367. The circuit of
FIG. 5
is generally limited to generating a current that is proportional to absolute temperature.
FIG. 6
illustrates a conventional bandgap circuit that can be found in U.S. Pat. No. 5,451,860. The circuit of
FIG. 6
is generally limited to generating a voltage output.
SUMMARY OF THE INVENTION
The present invention concerns an apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to generate a first current in response to a reference voltage. The first current may vary as a function of temperature. The second circuit may be configured to generate a second current to counteract for the variations of the first current. The second current may vary as a function of temperature. The third circuit may be configured to generate a third current in response to the first current and the second current.
The objects, features and advantages of the present invention include providing a bandgap reference circuit that may (i) not require an operational amplifier which may limit headroom, (ii) directly generate currents (iii) minimize the need for extra circuitry to maintain stability in a feedback loop, (iv) provide a simple modular design, (v) provide a PTAT current, an inverse PTAT current, or combination of both currents as outputs, and/or (vi) provide a low voltage operation (e.g., may operate down to 2.1 volts or lower across all process corners).
REFERENCES:
patent: 3781648 (1973-12-01), Owens
patent: 4450367 (1984-05-01), Whatley
patent: 4849684 (1989-07-01), Sonntag et al.
patent: 4935690 (1990-06-01), Yan
patent: 5049806 (1991-09-01), Urakawa et al.
patent: 5451860 (1995-09-01), Khayat
patent: 5559425 (1996-09-01), Allman
Kirkland Brian
Meyers Steven
Williams Bertrand J.
Cypress Semiconductor Corp.
Maiorana P.C. Christopher P.
Patel Rajnikant B.
Wong Peter S.
LandOfFree
Low supply voltage BICMOS self-biased bandgap reference... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low supply voltage BICMOS self-biased bandgap reference..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low supply voltage BICMOS self-biased bandgap reference... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2475374