Flexible circuit for droop detection

A method of monitoring a power supply, the method comprising:

• receiving a binary number;
• creating a pulse-density modulated signal referenced to a first supply voltage and scaled based on the binary number;
• level shifting the pulse-density modulated signal to produce a level-shifted pulse-density modulated signal referenced to a clean supply voltage;
• and
• lowpass filtering the level-shifted pulse-density modulated signal to create an analog signal;
• and
• comparing the analog signal to a monitored supply voltage to detect a droop in the monitored supply voltage.

A data processing system, comprising:

• an integrated circuit including at least two processor tiles each comprising:
• a processor core comprising digital logic, a local clock providing a clock signal for synchronizing the digital logic, and a local power supply monitor for monitoring a respective monitored local supply voltage, each power supply monitor comprising:
• a delta-sigma modulator including an input receiving a binary number and an output providing a pulse-density modulated signal referenced to a first supply voltage, the delta-sigma modulator operable to scale the pulse-density modulated signal based on the binary number;
• and
• a droop detection circuit including:
• a level shifter including an input receiving the pulse-density modulated signal and an output providing the pulse-density modulated signal referenced to a clean supply voltage;
• a lowpass filter including an input coupled to the output of the level shifter and an output;
• and
• a comparator including a first input coupled to the output of the lowpass filter, a second input receiving a respective monitored local supply voltage, and an output, the comparator producing a droop detection signal at said output responsive to the respective monitored local supply voltage dropping below a predetermined level relative to the first input.