Bandgap reference voltage startup circuit

Details Bandgap reference voltage startup circuit Bandgap reference voltage startup circuit

2000-09-29

2002-05-21

Smith, Matthew (Department: 2825)

Miscellaneous active electrical nonlinear devices, circuits, and

Specific identifiable device, circuit, or system

With specific source of supply or bias voltage

C327S541000

Reexamination Certificate

active

06392470

ABSTRACT:

FIELD OF THE INVENTION
The present invention is directed to bandgap reference circuits which provide a reference voltage independent of temperature. Specifically, a start-up circuit for a bandgap reference circuit is described whose operation is independent of power supply variations, which is an especially useful feature in battery operated circuits.
BACKGROUND OF THE INVENTION
Bandgap reference circuits are used in numerous RF analog circuit applications to provide a very stable reference voltage. For example, a wireless, radio frequency (RF) telephone is typically operated with a battery capable of generating a raw voltage between 2.7 to 5.5 volts, depending upon its state of discharge. Many of the circuit elements comprising the telephone, such as a voltage controlled oscillator, cannot operate properly without a stable and accurate reference voltage. Although a bandgap reference circuit can provide an accurate and stable reference, it has its own operational deficiencies.
A bandgap reference circuit has two stable states, an off state, that does not provide a reference voltage, and an operational state, that does. When power is applied to a bandgap circuit, the circuit enters the off state, in which no current flows through the bandgap reference circuit. The bandgap reference circuit remains in the off state until an external circuit forces it to transition to the operational state. Once the operational state has been established, the external start-up circuit must be electrically disconnected from the bandgap reference circuit so that the start-up circuit no longer influences the circuit operation.
SUMMARY OF THE INVENTION
The invention provides a start-up circuit for a bandgap reference circuit that will perform its intended function irrespective of substantial voltage variations of a power supply. The invention is comprised of a bandgap reference circuit, a start-up circuit that is electrically connected to the bandgap reference circuit, and a supply-independent biasing circuit that is electrically connected to the start-up circuit. The start-up circuit forces the bandgap reference circuit to transition to its operational mode when power is supplied to the two circuits. A supply-independent biasing circuit is integrated with the start up circuit to provide the proper operation of the start-up circuit for any supply voltage that supports the bandgap reference circuit's operational state.


REFERENCES:
patent: 3648154 (1972-03-01), Frederiksen et al.
patent: 4339707 (1982-07-01), Gorecki
patent: 4684878 (1987-08-01), Giordano
patent: 4857823 (1989-08-01), Bitting
patent: 5084665 (1992-01-01), Dixon et al.
patent: 5087830 (1992-02-01), Cave et al.
patent: 5545978 (1996-08-01), Pontius
patent: 5610506 (1997-03-01), McIntyre
patent: 5686823 (1997-11-01), Rapp
patent: 6034562 (2000-03-01), Bonet et al.

Affiliated with

Also associated with

Rating

Bandgap reference voltage startup circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Bandgap reference voltage startup circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bandgap reference voltage startup circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2871703