Nordic Semiconductor ASA
VOLTAGE MONITORING

Abstract:

A voltage monitoring circuit portion is arranged to monitor a negative supply voltage (V.sub.neg) and comprises a negative voltage generator arranged to generate the negative supply voltage (V.sub.neg) and to output the negative supply voltage (V.sub.neg) at an output terminal. A capacitor is arranged so that a first capacitor plate is connected to the output terminal of the generator and to a reference node via a potential divider. The potential divider is arranged to produce a monitor voltage (V.sub.monitor) between the resistors, where the reference node is supplied with a positive predetermined reference voltage (V.sub.ref). A comparator compares the monitor voltage (V.sub.monitor) to a threshold voltage (V.sub.ref_low) and to produce an output signal having a first value when the monitor voltage (V.sub.monitor) is below the threshold voltage (V.sub.ref_low) and having a second value otherwise. The negative voltage generator is enabled only when the output signal has its second value.