초록 ▼

A system and method for detecting brown-out conditions in a microcontroller, enabling a user to program the brown out detection system, and distinguishing between real brown-out events and transitory voltage swings without requiring expensive and time consuming logic. The invention compares a sense

A system and method for detecting brown-out conditions in a microcontroller, enabling a user to program the brown out detection system, and distinguishing between real brown-out events and transitory voltage swings without requiring expensive and time consuming logic. The invention compares a sense voltage to a reference voltage and filters the resulting signal to distinguish between a true-brown out signal and transitory voltage swings. The invention uses one or more program bits that vary the ratio of the supply voltage and the sense voltage. That is, the sense voltage is programmable and is dependent upon the value of the supply voltage and the value of the program bits. The present invention generates a comparison output signal based upon the comparison of the supply voltage and the sense voltage. The comparison output signal is filtered to distinguish between a real brown-out event and transitory voltage swings.

대표청구항 ▼

[ What is claimed is:] [1.] A system for detecting a brown-out condition in a microcontroller, the microcontroller receiving a supply voltage signal, the system comprising:a programmable voltage generator, disposed to receive the supply voltage signal and a first programming signal, for generating a

[ What is claimed is:] [1.] A system for detecting a brown-out condition in a microcontroller, the microcontroller receiving a supply voltage signal, the system comprising:a programmable voltage generator, disposed to receive the supply voltage signal and a first programming signal, for generating a first voltage signal having a voltage level that is substantially equal to a first percentage of said supply voltage if said first programming signal has a first value, and is substantially equal to a second percentage of said supply voltage if said first programming signal has a second value; said programmable voltage generator includes:one or more drop resistors having a first input node and a first output node for receiving said supply voltage at said first input node;a first switch resistor positioned between said output node and a low voltage node; anda first programmable switch coupled in parallel to said first switch resistor and receiving said first programming signal, said first programmable switch forming a low impedance path across said first switch resistor when said first programming signal has said first value, said first programmable switch forming a high impedance path across said first switch resistor when said first programming signal has said second value;a voltage reference generator for generating a voltage reference signal;a comparator, disposed to receive said first voltage signal and said reference voltage signal, for comparing voltage levels of said first voltage signal and said reference voltage signal and generating a comparator output signal representing the result of said comparison; anda filter for filtering said comparator output signal and for distinguishing between real brown-out condition from a transient voltage swings that do not represent a real brown-out event.