Power supply detection circuitry and method
AssigneeSTMicroelectronics S.r.l.
InventorsDavid C. McClure, Rong Yin
Life of this patent
Estimating the term…
Abstract
A circuit and method are disclosed for monitoring the voltage level of an unregulated power supply. The circuit includes a voltage reference circuit for generating a first reference voltage signal and a trim circuit which generates a trimmed reference voltage signal based upon the first reference voltage signal. A comparator compares the unregulated power supply voltage to the trimmed reference voltage signal and asserts an output signal based upon the comparison. The output signal is fed back as an input to the trim circuit so that the trim circuit provides a hysteresis effect.
Claims25
A supply voltage level detection circuit, comprising:
- a voltage reference circuit for generating a first reference voltage signal;
- a voltage follower circuit, coupled to the voltage reference circuit, for receiving the first reference voltage signal and generating a second reference voltage signal based upon the first reference voltage signal;
- and
- a compare circuit, coupled to the voltage follower circuit, for comparing a signal representative of a supply voltage level to the second reference voltage signal, and generating an alarm signal having a value based upon the comparison, a voltage difference between the first and second reference voltage signals being based upon the state of the alarm signal.
A method of monitoring the voltage level of a supply voltage, comprising:
- generating a first reference voltage signal;
- receiving the first reference voltage signal and generating a second reference voltage signal based upon the first reference voltage signal, the second reference voltage signal being a trimmed signal;
- and
- comparing a supply signal representative of a supply voltage level to the second reference voltage signal, and generating an alarm signal having a value based upon the comparison, the second reference voltage signal being based upon the comparison.
An integrated circuit, comprising:
- a first circuit for receiving a reference signal representative of a reference voltage and generating a trimmed reference signal based upon the supply signal;
- and
- a comparator circuit, coupled to the first circuit, for comparing the trimmed reference signal to an unregulated supply signal and generating an output signal based upon the comparison;
- the first circuit including hysteresis circuitry for varying the voltage of the trimmed reference signal based upon the output signal.
Dependencies are inferred from the claim text.