US 12,282,047 B2
Low power and high accuracy voltage monitor with built-in reference
Ricardo Pureza Coimbra, Paterna (ES); and Mateus Ribeiro Vanzella, Valencia (ES)
Assigned to Analog Devices International Unlimited Company, Limerick (IE)
Filed by Analog Devices International Unlimited Company, Limerick (IE)
Filed on Mar. 3, 2023, as Appl. No. 18/177,868.
Prior Publication US 2024/0295589 A1, Sep. 5, 2024
Int. Cl. G01R 19/165 (2006.01)
CPC G01R 19/16519 (2013.01) 20 Claims
OG exemplary drawing
 
1. A voltage monitoring circuit having a built-in reference and configured to monitor a voltage, the voltage monitoring circuit comprising:
a closed loop circuit branch including:
a first bipolar junction transistor (BJT) having:
a first collector configured to produce a first collector current, wherein the first collector current is a function of the monitored voltage; and
a first emitter coupled to a reference node;
a biasing network coupled to a first base of the first BJT and configured to generate a first voltage dependent at least on the monitored voltage to bias a second BJT, the biasing network including a first current source configured to sink a first current that is proportional to the first collector current; and
a second current source coupled to a power supply node and configured to source a second current that is proportional to the first collector current to a current comparison node;
the second BJT having:
a second base coupled to the first voltage;
a second emitter coupled to the reference node;
a second collector coupled to the current comparison node and configured to receive a second collector current,
wherein the current comparison node is configured to generate a signal representing a comparison between a representation of the second current and a representation of the second collector current.